Subterror Fiendess and Trap Monster interaction

  1. Bug description
    When I have 5 monsters in my main monster zones I am allowed to activate the effect of Subterror Fiendess to set a card face-down and summon a Subterror monster from hand/GY. On resolution, though, the effect doesn’t do anything

  2. Bug reproduction steps
    Have 5 monsters in Main Monster Zones, including a Trap Monster, a Subterror Fiendess and another Subterror monster in Hand/GY.
    Activate effect of Fiendess by targetting the Trap Monster

Replay code

7Z0HeBTF34Bn9+7gEsABCyKoBAUF6R1UIPTekaqSEAIEQg3dhoK9F8Qugr1i7xUs2HsXBewN7PUv37532b3LlWXn2Jy7Pt/x5L2Qmdv2e2d2dm9nRmhCiB3Gi3de1XUDfbqXlRXPnFS6pHnPkdMK581plje6eF5ZyexZXVq1iPxrltdzQen8BfOKu8wqXjB/XmFps7xhCyaVlhQNLF4yavaM4lldZi0oLQ2x0Fq9CucXtuhZWlI8a/6I4jmlhUuqGH8N9y2cWUxK1WHGX4rntSp/b12dhMHFZWWFU4vLdmftxZPj/xTqVVw0o5WxhICu1czJOWHkkrL5xTNb9JxdWlpcNN/YxLIWfYtnFc8rKWoxqKRsfkHrCRPKs/RYMr94wlHN8maWFc2eV1oyKbZT7Zzu1KSOHQvbF7Xv0Lpz23bFrTp1Puoojtaewnz1KHu9WXNdE/pjuVUe0HMCxp9yqwQN/qwNblrUtuf86d17lg0c1rpl+5KpffuO7lhSPHjSkKYlM4sGDC2d16t7We+xU4uXjBs3fe7ioeNnlo6YN2Zo93aFswZ1XDqsZ9mQkn6Du48bN37mksXjZo+a1qeoZVm7XtPnjB3Re1Cvvi3HzG8zsHe7ojktFxYumjql3/y5Q6YNHjyq9eTB44aPnrZoUctpo/p1atWptLR7m14zS2Z1n9m7V+u5LcfNHDR4StHAReMm9+kweFj7Vk17tBk1e/CM0tYlY5bO7zFjyZTxHRaPnVNcuHTR9F5tOoyeUjZ32pCivgP7thvdue2IHtPmLWzaetbIntPbL506qFevKUvaT+/Zq2jgoMKhfUcMn9m9e5cuQQ7Avx0htqHKxBJj+WWhiWUlS4vDExdGl2qkyAprnnBUOJwTMvJvC0V/qvIfLVI0wsb/9BzUzakKwiAH5IJqoDqoAXYDEtQEtcDuYA+AMDl7gdpgb1AH7APqgnpgX7Af2B/UB3mgATgAHAgagkbgIHAwaAyagENAU9AMNActQEtAUcppDdqAtqAdaA86gI6gE+gMDgWHgcNBF9AVdAP5oDvoAXqCXqA36AP6gn6gPxgABoJBYDAYAoaCYWA4GAFGglHgCDAajAFjwTgwHkwAR4KjwNFgIigAhWASKAKTQTGYAqaCaaAETAczQCmYCWaB2WAOmAvmgTIwHywAC8EisBgsAUvBMeBYcBw4HpwAloETwUlgOVgBTgangFPBaeB0cAY4E5wFzgbngHPBeeB8cAG4EFwEVoKLwSpwCbgUXAYuB1eAK8FV4GqwGlwD1oC14FpwHbge3ABuBDeBm8Et4FZwG7gd3AHWgTvBXeBucA+4F9wH7gcPgAfBQ+Bh8Ah4FDwGHgdPgCfBU2A92ACeBs+AZ8FzYCN4HrwAXgQvgZfBK+BV8Bp4HbwB3gRvgbfBO+Bd8B54H3wAPgQfgU3gY/AJ2Ay2gK3gU/AZ+Bx8Ab4EX4GvwTfgW/Ad+B5sA9vBD+BH8BP4GfwCfgW/gd/BH+BP8Bf4G/wP/AN2AGHUdjlUeTk6CIAg4GSeUwVUBWGQA3JBNVAd1AC7AQlqglpgd7AH2BPsBWqDvUEdsA+oC+qBfcF+YH9QH+SBBuAAcCBoCBqBg8DBoDFoAg4BTUEz0By0AC1BK9AatAFtQTvQHnQAHUEn0BkcCg4Dh4MuoCvoBvJBd9AD9AS9QG/QB/QF/UB/MAAMBIPAYDAEDAXDwHAwAowEo8ARYDQYA8aCcWA8mACOBEeBo8FEUAAKwSRQBCaDYjAFTAXTQAmYDmaAUjATzAKzwRwwF8wDZWA+WAAWgkVgMVgCloJjwLHgOHA8OAEsAyeCk8BysAKcDE4Bp4LTwOngDHAmOAucDc4B54LzwPngAnAhuAisBBeDVeAScCm4DFwOrgBXgqvA1WA1uAasAWvBteA6cD24AdwIbgI3g1vAreA2cDu4A6wDd4K7wN3gHnAvuA/cDx4AD4KHwMPgEfAoeAw8Dp4AT4KnwHqwATwNngHPgufARvA8eAG8CF4CL4NXwKvgNfA6eAO8Cd4Cb4N3wLvgPfA++AB8CD4Cm8DH4BOwGWwBW8Gn4DPwOfgCfAm+Al+Db8C34DvwPdgGtoMfwI/gJ/Az+AX8Cn4Dv4M/wJ/gL/A3+B/4B3ANlCOMFn2OBnQQAEEQAlVAVRAGOSAXVANcO+XUALsBCWqCWmB3sAfYE+wFaoO9QR2wD6gL6oF9wX5gf1Af5IEG4ABwIGgIGoGDwMGgMWgCDgFNQTPQHLQALUEr0Bq0AW1BO9AedAAdQSfQGRwKDgOHgy6gK+gG8kF30AP0BL1Ab9AH9AX9QH8wAAwEg8BgMAQMBcPAcDACjASjwBFgNBgDxoJxYDyYAI4EXKLlHA0mggJQCCaBIjAZFIMpYCqYBkrAdDADlIKZYBaYDeaAuWAeKAPzwQKwECwCi8ESsBQcA44Fx4HjwQlgGTgRnASWgxXgZHAKOBWcBk4HZ4AzwVngbHAOOBecB84HF4ALwUVgJbgYrAKXgEvBZeBycAW4ElwFrgarwTVgDVgLrgXXgevBDeBGcBO4GdwCbgW3gdvBHWAduBPcBe4G94B7wX3gfvAAeBA8BB4Gj4BHwWPgcfAEeBI8BdaDDeBp8Ax4FjwHNoLnwQvgRfASeBm8Al4Fr4HXwRvgTfAWeBu8A94F74H3wQfgQ/AR2AQ+Bp+AzWAL2Ao+BZ+Bz8EX4EvwFfgafAO+Bd+B78E2sB38AH4EP4GfwS/gV/Ab+B38Af4Ef4G/wf/AP2AHEMZVcY4GdBAAXMfnhEAVUBWEAXc4cnJBNVAd1AC7AQlqglpgd7AH2BPsBWqDvUEdsA+oC+qBfcF+YH9QH+SBBuAAcCBoCBqBg8DBoDFoAg4BTUEz0By0AC1BK9AatAFtQTvQHnQAHUEn0BkcCg4Dh4MuoCvoBvJBd9AD9AS9QG/QB/QF/UB/MAAMBIPAYDAEDAXDwHAwAowEo8ARYDQYA8aCcWA8mACOBNwAyTkaTAQFoBBMAkVgMigGU8BUMA2UgOlgBigFMwH3TnJmgzlgLpgHysB8sAAsBIvAYrAELAXHgGPBceB4cAJYBk4EJ4HlYAU4GZwCTgWngdPBGeBMcBY4G5wDzgXngfPBBeBCcBFYCS4Gq8Al4FJwGbgcXAGuBFeBq8FqcA1YA9aCa8F14HpwA7gR3ARuBreAW8Ft4HZwB1gH7gR3gbvBPeBecB+4HzwAHgQPgYfBI+BR8Bh4HDwBngRPgfVgA3gaPAOeBc+BjeB58AJ4EbwEXgavgFfBa+B18AZ4E7wF3gbvgHfBe+B98AH4EHwENoGPwSdgM9gCtoJPwWfgc/AF+BJ8Bb4G34BvwXfge7ANbAc/gB/BT+Bn8Av4FfwGfgd/gD/BX+Bv8D/wD9gBRNCABnQQAEEQAtzMzakKwiAH5IJqoDqoAXYDEtQEtcDuYA+wJ9gL1AZ7gzpgH1AX1AP7gv3A/qA+yAMNwAHgQNAQNAIHgYNBY9AEHAKagmagOWgBWoJWoDVoA9qCdqA96AA6gk6gMzgUHAYOB11AV9AN5IPuoAfoCXqB3qAP6Av6gf5gABgIBoHBYAgYCoaB4WAEGAlGgSPAaDAGjAXjwHgwARwJjgJHg4mgABSCSaAITAbFYAqYCqaBEjAdzAClYCaYBWaDOWAumAfKwHywACwEi8BisAQsBceAY8Fx4HhwAlgGTgQngeVgBTgZnAJOBaeB08EZ4ExwFjgbnAPOBeeB88EF4EJwEVgJLgarwCXgUnAZuBxcAa4EV4GrwWpwDVgD1oJrwXXgenADuBHcBG4Gt4BbwW3gdnAHWAfuBHeBu8E94F5wH7gfPAAeBA+Bh8Ej4FHwGHgcPAGeBE+B9WADeBo8A54Fz4GN4HnwAngRvAReBq+AV8Fr4HXwBngTvAXeBu+Ad8F74H3wAfgQfAQ2gY/BJ2Az2AK2gk/BZ+Bz8AX4EnwFvgbfgG/Bd+B7sA1sBz+AH8FP4GfwC/gV/AZ+B3+AP8Ff4G/wP/AP2AFEyIAGdBAAQRACVQDfiuSEAV+W5OSCaqA6qAF2AxLUBLXA7mAPsCfYC9QGe4M6YB9QF9QD+4L9wP6gPsgDDcAB4EDQEDQCB4GDQWPQBBwCmoJmoDloAVqCVqA1aAPagnagPegAOoJOoDM4FBwGDgddQFfQDeSD7qAH6Al6gd6gD+gL+oH+YAAYCAaBwWAIGAqGgeFgBBgJRoEjwGgwBowF48B4MAEcCY4CR4OJoAAUgkmgCEwGxWAKmAqmgRIwHcwApWAmmAVmgzlgLpgHysB8sAAsBIvAYrAELAXHgGPBceB4cAJYBk4EJ4HlYAU4GZwCTgWngdPBGeBMcBY4G5wDzgXngfPBBeBCcBFYCS4Gq8Al4FJwGbgcXAGuBFeBq8FqcA1YA9aCa8F14HpwA7gR3ARuBreAW8Ft4HZwB1gH7gR3gbvBPeBecB+4HzwAHgQPgYfBI+BR8Bh4HDwBngRPgfVgA3gaPAOeBc+BjeB58AJ4EbwEXgavgFfBa+B18AZ4E7wF3gbvgHfBe+B98AH4EHwENoGPwSdgM9gCtoJPwWfgc/AF+BJ8Bb4G34BvwXfge8A3tDnbwQ/gR/AT+NlA7v+//v8V/5J8d89X8ka7PpRfXwh+GsvGUvJ9PuVYryLyC4zfd1y9Q6xqYFSK+SLMewOxTPDi632+zs8zfh6oVvHH6avi8rVKW37r7WN0ka+HeTeXb+wi3+5Flr8hR4h24di76vL/bmy0fvMDYd7N5QfLl89//9mxY0f8T2bLD1ba8nuOXWQcn1CY98pbfpVKW/6Th31tLL9qmPfKWL4281OjhITDvFfG8tetucNYfk6Y98pbfm6lLf/H9d8bx79amPcG0UVHXlr5j1lmnZbdgPFzctzya7UzTrf51cO8Jy5fN34OrRr9v/m+sxefCcUt/9rLmhrHp0aY9/jl8wvVQWn5cksVlr86bvklg4xTef5uYd4Tt583bu/wMt939jL3W7JxPDyjV9HyzXor2++S5754aksfL0LjjikKfrByhr6i0fHixs+7atqKQzWZa2XgUir5JdGifmQ3BHeXRLofWd3KqNln5LmzA6NLDNtljGTezcqs7TwzJ02+pzWWrBeIaHzZayMgubzrqfYw8RUUjrKZy+eICl3L5T0YOSu6u3yiJXQ9l3fdtNLF5WOC0AO5vAd39qEMlo9lRksml3c3ly851DwsaJihOy4PPN/I4vXGQvKYI4Vab6IJyeOOjjTfUzjUnMcmHWteWyhoTnldG12ynsdOLNvb0jzxMJnppqbp0k3N0qWbmqRLN8OcmC55XFQ5TDxeGg2NLiSPmToKTT3hMDQ8ruo4NPsJhdDw+KtvQsOxUg5NZKl8qElQSOOE6Sw0BwiHoeFIOw5NQ6EQmkbCR6Hh8Wjl0PA4deRc3kCE2DK2ni1gLyMn+8YpDkF0FzI/BNFdTH8Iooc4g0PAI+GO3DpEOHSLA+rYrWZCwa3mfjqwPFKv7BaP4EdOnm2s9Yb1ECdryYP5lES9qvGnCltHjsS1tzYX1MfKEo6c8DXJc/2Rk3NfTfJ4v6PotxMOo083gW6iYvR3trUpF0RXA8dm0CVhuciuGdHIJ5sh6RqhHHm6UkSi0k+T9KiIWlB7+2hCFsawfLLRz2KyiFigBwtEtPEXyWXk4F23Fpn+lb/THOUbRYcO9k+vr2nlK5H070hV/ZEeqf7o+5HtUhrduAxKaURVfvKEzDd/76/J7sJhweghHBaMnsKlgtFLKBSM3sJHwaA3kHLBofdQXJXJUawpqDKFpE8RJ2OjsNSM1J2B88qPdXmOpC2gA1Lk1sIASTckRwYMFA4NoDuT4xPjYKEQZbpH+SbKdONSjjLdvhxFY7hwGA26jzmOxkihEA26o/kmGnSbU44G3eziTlCRZkoolE8Sne/MZkqowtaFQ8nNlLHmgvpYWcKRXJqk757ZTKELn6PoTxAOo09XwMTaOP5nZ1tuLYjuhI7NoNuhZ5opdH9UjnyBiDVTCoVpwdbb/jRC1iDWTJkkUjRTIrmMHFuM9wbG9pkVsFa+uflVjBVVjXtP3OQ0L1kkYs2U8pVI1m42U/hb0i3ZYpFcSqMf9uCFKv1QzWbKVPN3o5lCr1RHBaNEOCwY9G51pWDQQ9ZxwaAnrW+CQY9f5YJDD+HylgX9hB0FbY5wGDT6G7sSNPosOw4afZt9EzT6YCsHjT7bjiK1UDiMFH2/XYkU/ccdR4p+5r6JFP3hlSPFV4Bx5yL2KxgM55NEr/ryFkkwWGHvjRxJa490vyd3h8j/jSySzviHidQW7Gx5VgjozO/IkGXCJUNOFAqGnCSSWyZRA9IbEjWgElombIiyAStEiqZkoTY7pEm+SDebkoyYsMvBZMQFR8FkVAZXgsnIDo6DyQgQngkmI1EoB5ORK8xmJgNYRFp37c24BCXjWaQr08GkTTjXXJrRYmL8C4fxT1qQdYAZP8NR/Bljw5X4M06H4/gznodn4s+4IsrxZxyS8tYSo5HscsAYzcRRwBjxxJWAMWqK44AxuopnAsYoL8oBY1SYaO1rxcIomJtulppkrBiz9mXImF0O5mrhMJjXCJeCuUYoBJOGlmeCea3IIJjXiVjtywg+0YbV6I3zg0KrG7vIZ1yfySLhIj+Sy8jBO99bm4/SmA9s0V+X8RjM9/zETU7zkgwgZF7kl69EMp6QeZFvXthzKEnnkEvGGkps+EaPZfpYRI9l5g3f6Malb/hGXUjR8L1FxC7ybzV/N05ZjJC0y4WGEZYcFRpGYXKl0DCSk+NCw4hPvgkUI1MpFypGsio/pTGe1S4HlPGwHAWUMbNcCSjjbjkOKONz+SagjCOmHFDGHdvlKDJumaMoMraZK1FkfDTHUWQcNd9EkfHelKP4hDDPb9Z2hY0fnrh4UqR44iKSK5y89fIpUeHGgZFFrhcuGLJBODTkaQMTREVDdrbVyvYwYJ5jexhYL7EltKv2RO1Ib0/UjhQtoedEBnYwIGDUDmu7wlrUjudFzA6twtaHk7deRsYTFDE7tFzJ6IK7bAejEzqygxEMF4mYHTvbYjPdNXMYPdGxOYyyWCTUzImakX5PomakKLmM5qhsBqM/Rs2wtissomYwJqRpRsUWfDh562Vk8EgRM0PkSoaS3GUzGIrSkRkMV3lhdG3hnW2tmZ41axhG07E1DLfZU1S0JmqF+m1uybCdylYwzGfUCmu54UDUCgb/NK0IVFh7OEVtFRklVMSsCORKxgzdZSsYc9SRFZ8YuENkx4qdHQ0lYzYLBWO2WJl3bozcKjIw4lOWyoeaGA58JlwIIWPCOgoh48b6MoRfCoUQfiUUQvi1yCCEjLW7y1FjrF5HUWM8X19GjTGIHUdtm1CIGmMaK0eNMZCjfZA0yVDIVh8khkTe5XAypLKjcDLssi/DyVDRjsP5m1AIJ0NPK4eToarpe6qPj46/Lxm22uq8xPDVuxxThr92FFOGyPZlTBnW23FMdwiFmHJrq61Qi6kVWyJqdXZimPFdDiXDlDsKJUOZ+zKUDL/uOJRVNIVQVt2VUDIMPB0E9QZalcQlW2vI2ZU15LrhRzWnflT3qx81VPzYTcUPuSvRY/j/6AVStxp1dc24QNLMDk5MCtCQpKpa7HZbJFdCzwjqf7m7uaA+ZhbN7OC0h7WOyP+1BtyfyV3Gp/ZMSMozkrRo0l4JSfWNJD2aVDshaX8jKRBN2jshaT8jKRhNqpOQtK+RFIom7ZOQVM9IqhJNqpuQVNdIqhpNqpeQtI+RFI4m7ZuQVMdIyokmMV+C+fXr/m6UnfpOy06eX8sO00lE77VrSXdS0wmZ8ggcoFKumLpCuVnU0CoG1nJ1UbByUF9dNtIqfHNLUk0ttIxPMS1GYxG5F1FTo8zRMSaSqzxH0sYxhwYVuj5SQw7Z2LJKl03csOoQp1Y19atVzdyyqrnZXDKski0ysaalGb1+umxl/j5Qk8x7UuFRq2BYtjHT++uyrfNIp394rp3TSLf3a6Q7uBXpjvGR7pRJpDtbkdbkoRXPvZwyzZ5yh1kVghbrKRfJlaKnXOT8y1w3/KIPkF3csKKrUyu6+dWKfJUWWff4yPfIJPI93YhKL6dR6e3XqPRRiUrf+Kj0yyQq/a0yqB28MBhp/waNK17avwNi7d+g1VqI5CJH3CtS/iITRJH7cDOLHGQWyS5ysBvBHxKrxqyFmHWDudLEkZhSVWVyqF/lGKYix3A3jvkIayGxY24dkjQuJG3JSL8e71Eqx/uI+MI4OvbJnRZGOabi1VL0IjT6Ld1YLf57N/4sx7kR1/FuxHWCX+PKxHMHi4pxDSdkqrCnR8XHlsnq6gn72MqJCTEVRkzLn9QoSIiplisL3YjpJDdiWuTXmE6Onf7C8fG0jWtxfFyZXHAPkTqucqqZs0lYyGluhKvEjXBN92u4ZmQSrtL4cM20C9csNyI0240IzfFrhOZmEqF58REqs4vQfLMWnBVtcRqX9gu0tKMvLDSvG/tqcpEbsV3sRmyX+DW2SzOJ7THxsT3WLrbHmdEyrvKZOrXCPZxwUJ6gqXSXW2Yurb8mT3Qe+6QFWTtykhuxX+7X2K/IJPYnx8f+FLvYn6pZN2JOcyNYp7sRrDP8GqwzMwnWWfHBOtsuWOdoabvJnRtX457nRiDPdyOQF/g1kBdmEsiL4gO50i6QF8fVuKu0il3kcsN82ZJPNmaRniwiFa8uCkR8Fznhfhe5S7XELnJCMnt15LmZBiLyN8lM1o6/k7rC3M08Ia+MOy1c5YagV7sh6Gq/CnpNJoKuUQneWjuBr42dNq5zI5jXuxHMG/wazBszCeZNKsG82S6Yt5jBnCNvdSOYt7kRzNv9Gsw7MgnmOpVg3mkXzLvMk1AT4zrsbjfCeY8b4bzXr+G8L5Nw3q8SzgfswvmgkcjsHnoDzZpxQT5k94mH3Yj5I27E/FG/xvyxTGL+uErMn7CL4JOxIqzLp9wI53o3wrnBr+F8OpNwPqMSzmftwvmc2a5ubx6NkNyope/+mTzO6fPWdZ+VJazVzL9xD02+EHfd96IbqrzkhiovZ65K0t6b6VlR5ZVMVHlVRZXX7FR5Pe668A3rurDNsHUhodUJCw69kVe+GbsuDOoFInpdGMll5OCd60Jz1TXLf5ibb3tu7N1a605e8i2t/NZvV3MV8m2zxdhNvmO8jxEVpTMPgpk/1eE28+xUyHfdEPI9vwr5fiZCfmBqZFx3f2j+blx3f1TZsdrkRqw+9musPskkVptVKo8tdpXHVq3CaAMcjZp69AG9T7XYE7s6553IQzjkKs+RtKbPNOsC//PKtuYLN6z5UnPeDz1+BVkx46tMzPhaxYxv7Mz4trIj+J0bEfzeyxHclkkEt6tE8Ae7CP5o1uKNhfzJujzQhPy5skP7ixuh/dXLof0tk9D+rhLaP+xC+6dmdk0VWqfh23T5lxVfXci/Kzu+/3Mjvv94Ob47MokvpS1x8KF08S0Q0RY40WPQDt7dnMVUcusnrT+syur+GtArWRemZ91lXUK6h3WpomegS1VdfewYU5fEdBm2C3eObt4QFDpLiHwrl5ti9dHFqw94JKtVtkPV3XCohpcd2i0Th6SbQaxp51At3bxSsJbP1QJPu+6up7gxFcmV6sbUHuaC+lhZwpHQaXJPax3m5N3C7Ea7l5VkzksuzG60ta0kc8p4YXaj3dtK6jl2kS7yqxhJ5d1o61hJfzeeHRT5QSOpvBvtPlZS6+1jjE8ZB8PsRltXj906q1fZzu/rhvP76epXxuliZ6ZnpTzsn0l5qK8rNLHy7HxvYEa6nyYPMOvP8UKf9P28IJGTB5oZ+muyYWWr0MgNFQ7yqwoHZ6JCY+NDW4Vaa4zgUjXynhSMFK98oTZnenSmEF1lPipnrb0mdiofUrHqjtzkCURv8jTVYzd5AtTh3OSJ5CrPkbSmZrp1k6d5ZVvfwg3rW3r5pN8qE7Nb68lDVe6s4WianS7dNDMxXbaxM6ttZRvQzg0D2nvZgA6ZGNAxmwZ0sjOgs5405ENQ0/JJOjTWLAxqFbYyqCVZIQ/Tzd6lZhZ5uFnVdJFddGss2YgHZlVl5k3sFBq/Y66I2NUNEbt5WcT8TETsbnyoTMTiYq4tXZjNdFdi0sONmPT0ckx6ZRKT3imuCaOFP33lEC38Ka4J+9gV/r56haFgiHdQK1w5yLg46qdXHL2lf9yF04B/U5qBbkgzyMvSDM5EmiFuSjPUTpphcRdWw/Xk0V9GVDyj1IzcZAhGnmEYGWutBhNOAdEcSVsyyjyrdDWzySN06zmE0cav50Z32uqjZC0uzU67KGn6rmtj3JB0rJclHZeJpOPjLrkneDV2R7oRu6O8HLujM4ndRDcrmAK7CqYwdoU6yauSFLkhyWQvS1KciSRT3JRkqp0k07xqRokbZkz3shkzMjGj1E0zZtqZMUtP33M5+bJ1ttnAyDezyDlm/dNdzv13LUuZJ3I457lhWZmXLZufiWUL9ITOsprVWXZh3AXMIq+GdbEbYV3i5bAuzSSsx7hZeRxrV3kcF3dxc7x1IRNZl7ZnmNtr+WQ7QY910tULRPyXD7rKlw+OXnKZHuukW74SeaLOAyuCRwIC7Cp/50eelOLW4s4mbt/ZrUVzz5K2bLl5uPKEXBHXuD/ZqwXsFDcK2KleLmCnZVLATs+mNGfYFcAzY43/s7wq0dluSHSOlyU6NxOJzsumROfbSXSBV8250A1zLvKyOSszMefibJqzys6cS4xEawy5S72q0WVuaHS5lzW6IhONrsymRlfZaXS1V81Z7YY513jZnDWZmLM2m+Zca2fOdeb9iFnEOjJI8/XWlyybG81mEPbckLxBTzHzSXly8swnN1qXxWYWa+aTm+Iui2/2qrW3uGHtrV629jbrCreiteYC0oU2pc23Z9PmO+xsXpfqfkyDTTdLXd4Z/wWzYfldloi6vNurIt7jhoj3elnE+9wU8f5siviAnYgPWvd1dPmQVZ+aToTlw4lfZBt/e8S6oaHLRyvPyJRfJVQ4WnZfNzzmhpGPe9nIJ9w08slsGvmUnZHr4+40brDsM50Jy6fjbqc9k7l9SeaY6a7Y96wb9j3nZfs2umnf89m07wU7+1607m1bLcLogzpCvqTHJvbRaGPykE4kV3mOxF2VL8fu2b3iVVNfdcPU17xs6ut6xRkT7C54Ih94I5s2vmln41teteZtN6x5x8vWvKtqzXvZtOZ9O2s+sM6a5pEKyQ9jX/7HrovLk5O7Mn5kXZ5YWczr4k3m5clk8WXAyPpx7HIlMh3IJ3HXzZu9qu8WN/Tdumv6pu155oq+n6rq+1k29f3cTt8v4hqAX1qn4wbfrI8IpuXlhvLJ9lXsdJyXa56OI7nKc8S/Iqfjr+Najt94Vc1v3VDzOy+r+b2uMDPVtmxqud1Oyx8sFa2jZHY2/FFP0dkwkitdZ8OfYi3Dn71q4i9umPirbvVvcmRi/ErcGdBGxbbfs2nbH3a2/elVK/5yw4q//20r/qdixT/ZtGKHnRV8BWuNZ60FPKqIHnBBkUDgX1YkGFBQJBTIoiJVAjaKVA2kef4tnM1NzPGqm7luuFnt33azuoqbNbIZ+N3s3JSBCg+O8vlw5MFRXdYMpLg+jeRKcaEvawXip6Eki9zdq8bt4YZxewYya9CnO4Jmuis27qViY+1A8iPLmdoo97azrU6CbRoDO0UfU94nkGJgp+ixSrGWugm2abmynldt29cN2/YLqI+nk+7oVUyv7KGVVEysH0geUimdiTLPzrQGgRSTPxZqs0OaPCAQux12oFelaeiGNI38Ks1BKtIcrCJNYztpmphm9NPkIYHkiSabBlQmmmxmLq2/Jpv/u54lrcM6eC3c8KylXz1rpeJZaxXP2th51jZg3Wpq51Ux2rshRge/itFRRYxOKmJ0thPjUK/acJgbNhzuVxu6qNjQVcWGbnY25AcqTKvDIw01tVqRaXW6ByrMpUBSXpXQMj7VI2Dd+c6rwtnKmkuhPEfSRvSMaxD18qqBvd0wsI9fDeyrYmA/FQP72xk4IK5BNNBS7u6Whkya0XgNByPLk4MCVhfTcLBARLuYRnIZOXh3OJC4o5ccnHDtF8yVQ8zGWn2hla9XDjW3PU/IYXFNseFeNXyEG4aPNBbygvCG4Wa6aUK69J3aP0rF/iNU7B9tZ/+YWDNtrFelGeeGNOP/i9JMUJHmSBVpjrKT5mivmjLRDVMK/oumFKqYMknFlCI7UyYbiQEhotNoFntVmyluaDP1v6jNNBVtSlS0mW6nzQyvmlLqhikz/4umzFIxZbaKKXPsTJlrtnoba3KeVdloQpZ5VaH5bii04L+o0EIVhRapKLTYTqElAXPyr2jfMLnU8kgX8hivenSsGx4d91/06HgVj05Q8WiZkbmeSO2R5dOJlj5BIU/yqj7L3dBnxX9Rn5NV9DlFRZ9TnehzWsB8koon7eI+fbqTT5/hVd/OdMO3s/6Lvp2t4ts5Kr6d68SY86x7nj0Wdg1puparRQaeNy7Yzg9Yo1oENXNtkVwJ3aj5j7zAvGd5uJlFXmjeXeoiL/KqmCuNDZsgYmKyw3ydYO5E4lQYmshA3Iv/i+KuUhH3Eq/G/9KAOeeOVmH2hHSem+mOY3/ZfzH2l6vE/gqVSutKu7b6VRUrKyM82hPVBNMayqutJDMyRpIWSVptJW1et1HX8quFI4EzoiGvMZJaiWgVpzcT0aIfyVWegxcXmJH1GQvm/5Hqbo1Z3XU1s8u15lc07c3jH5LXBmLP/AUSwpPcA/I6c0v7WFnCkVaAJq8PWD0gPzQ+KG8wr3z7avJGrxaumwJWd33rrN+4/MPWUU5zhJM0uvnfK0hpu6btckG6RaUg3apSkG6zK0i3m/b00+QdFYsHJaemHupOtnWx4lGzYvEoz8ErZfG4s2JJPU8XWrRXWp68KxAb0cDqtxbJVZ4jfjciC7u7YtmOLCwYXdg9cQsLmguL5CrPkbSwe81d76/J+7xacO43Nqy+qFhwUirxwH+xUDyoUigeUikUD9sVikcszaw9NPtaPhpI0dcykitdX8vHAtY3q4971bInnFr2ZCB7D5XE78Eum/SUiknrVUzaYGfS016N+DNOI/6sXyP+nErEN6pE/Hm7iL9g3fUzLpxf9Gr4X3Ia/pf9Gv5XVML/qkr4X7ML/+uBhJEVg+UjK2ryjUDcyIoiKN+Ma7i/5VVR3nYqyjt+FeVdFVHeUxHlfTtRPohreH8YqDjOnAiG5UeB5Cn8NsW1WD9Ob0xaI7LSm+cTp8Zs9qsxW1SM2apizKd2xnwWa0h+7tXgf+E0+F/6NfhfqQT/a5Xgf2MX/G+t6sA8CiH5XSB9N9LkW0rfW2cmK0s4cs9Fk9vizkTbvarWD07V+jFztdJeyWZFrZ9U1PpZRa1f7NT6Ne5M9Ft8G8U44/yeeBYKa/KPgMpEbn8mihvKlX/Fncf+/nd9S9pg6wD/z6lv//i1Ktuh4ht07JsWtPFND1rnsUDQo8En4o6CHwr6NPhVggrBr6oS/LBd8HOCaWcCzA3GzkLVvCpGdadi1PCrGLupiCFVxKhpJ0YtM/rGWWj3YIWpyrVwmOEz8sm2RzA2w59WIKLdryK5jBy8NxDR2kWUv7NMRk/4WYu95yduWpqX3DMYm+GvfCVyL+Nv1fhbA6Gzq/xd1g6qDytibnXSWvc2D0WekHXM341T5T5eLRR1nRaKen4tFPuqFIr93JRhf7tCUz92Ks3zqhwNnMpxgF/lOFBFjoZuytHITo6DvGrEwU6NaOxXI5qoGHGIm0Y0tTOimXkyaSxk86CIdZJo4VVVWjpVpZVfVWmtokobN1Vpa6dKu6DZGUJofL0t21u+6EJ28KovHZ360smvvnRW8eVQg2uFO74UiGhjO/Kwg67n8h4UiU/Fpng5HBBBHmbn4+GWfkEhu3hVv65O9evmV/3yVfTrHlQf+jOdfma6qV9iuuxhp0/PoLCGpWUNLIUtkb1SbGJ0E9JvYnQT0m9idBdTbGJvr3rbx6m3ff3qbT8Vb/tnU4oBdt4ODMbutVubkm7KRDkoWP4ocr6ZRQ4Oll8hdpdDKs++lGZV2HM7+4Y6tW+YX+0brmLfCK/GaaTTOI3ya5yOUInT6GzWEmPsaomxcbVEghIiuZYYZ9USZhY5PlZLTEhvX9KiKqZXsn1HOrXvKL/ad7SKfRO9GqcCp3Eq9GucJqnEqSibtcRku1qiOJh2mOgpwdhXb1O9KtY0p2KV+FWs6SpizcimWKV2Ys007emnyVnBhClzw0E5O+70pFXY1CAPCiSsao65tP6anJu5i0kLNtNdcXGeUxfL/OrifBUXF2TTxYV2Li4KWt+ILfaqPEucyrPUr/IcoyLPsdmU5zg7eY73qjEnODVmmV+NOVHFmJOyacxyO2NWBM3b0mEhT/aqPqc41edUv+pzmoo+p2dTnzPs9DnTq8ac5dSYs/1qzDkqxpybTWPOszPm/GD5zZtZZvzkBWaTZ6680Ks+XeTUp5XBio+LM3n4xcH0k7Ml93NYFazYzyFu8vBLgrHL3Eu9eqguc3qoLq+8opey2Jh5drnoXaFS9K7MZtG7yq7oXW3aY1zmrg7G95PQ5DWJ2oZy5Rozv3Ehu9b4fZXInm2RsVWWx2zrV0MIflLljRzma51ad51fK/zrVay7IZvW3Whn3U1B64L2Zq9WWbc4ledWv8pzm4o8t2dTnjvs5FkXLB/4b3b6SkDeadZlEyI55F2mcfPk3V417h6nxt3r1T24z+ke3O/XMvOASpl5MJtl5iG7MvNwMNbCjjoiHwlaLexHverTY059ejyuThCa2SUm4Qg9EasTyCGfjNUJT3n1CKx3egQ2eHUPnna6B8/4tU54VqVOeC6bdcJGuzrh+bg6IRpj+UKsTnjRqz695NSnl+PqBF3bYOzq9uQj9EqsTiCHfDVWJ7zm1SPwutMj8IZX9+BNp3vwll/rhLdV6oR3slknvGtXJ7wXNG/9C02+71V9PnCqz4d+1ecjFX02ZVOfj+30+SSmjy43e1WfLU712epXfT5V0eezbOrzuZ0+XwT/3RuK+UZLIFw1MWfcofrSqTlf+dWcr1XM+Sab5nxrZ853QWHNlPW9VQlpQm7zaiW03alKP/hVpR9VVPopmyr9bKfSL8GEGbN+tXzShfzNqz797tSnP/zq058qPv2VTZ/+DjqYiuZ/lkZBIf/xqkY7nGokQj7ViPHwHGvEl8ZZ04gx53eqUZDpMciUOINWyMmnq4Q86l3VkEPvwn71LkfFu9xselfNiTnVQ+bwVWPL/tI0Yzsi05swk1aNUGwmLWtrI7lSzCAkdwuZM2mZWaQMWTNp1fSqoLWMDesmKgrKTjNVgrkjqWbTSgrt7n4VeA8Vgff0ahz3CqWfqi+ds0l7V9uvMdxbJYZ1slkJ7ROyaZPXDYnYE8n1vKrWvm6otZ9f1dpfRa362VQrz06tBl616QA3bDrQrzY1VLGpUTZtOsjOpoPNxs2saOsoqMnGoRSDw0Ynz2gSsh64jLSDDgkJ61Hepl71spkbXjb3q5ctVLxsmU0vW9l52do0q58m24TMx3rNcIVl21DCkOjG39qZn+mvyfb/ro3pB9DvEIuHZWM4IZOVuaNfreukYl3nbFp3qJ11h4Wsx3wP96pAXVQE6upXgbqpCJSfTYG62wnUw6vW9FSxppdfremtYk2fbFrT186aftbVotBkf68qNEBFoYF+VWiQikKDs6nQEDuFhobM8fA1a5xPOczuE8O96tkIFc9G+tWzUSqeHZFNz0bbWTMmVlXpcqxXFRqnotB4vyo0QUWhI7Op0FF2Ch3tVWsmqlhT4FdrClWsmZRNa4rsrJlsXtw3FrLYqoQ0Iad4VaepKjpN86tOJSo6Tc+mTjPsdCoNxUbW7zR8my5nWk7pQs7yqlOzVZya41en5qo4Nc/IvF5kx6kCER19H2OEHsjl3dGw+k5H3y+zc3a+pWhQyAVeVXShiqKL/KroYhVFlxiZl4vsKGqmm4ompsuldoodYyY2EEGWwFaypsjkI8em2I3oajKfSGBnuxE9DCl24ziv+n+8iv8n+NX/ZSr+n+glcU6y8395SGVW3RXml6f5ZhZ5csgaw/sUr34heqqKoaf51dDTVQw9I9V33tEJUc+M+477LK+G9GyVkJ7j15CeqxLS87xU6ZxvV+lcEPdd94WmiG2q/DpBF1puWOjB3HyyXRSKTboaLBDRlmgkl5GD9wYi2j7kpZUfBnqI0Vax3hM3Lc1LrgzFJl0tX4m82Pjb3iLSOgjxN7N1wGGNtBBWhZJnuop+uPKOebqGjpkejUmydfIS87DnCXmp+Xt/TV7m1UJ+uUohv8KvhfxKlUJ+lZ+Eu9quElgdsh49uMarAq5REXCtXwW8VkXA6/wk4PV2At7gVetuVLHuJr9ad7OKdbf4ybpb7ay7rWJ7h+0PBrR8km6PuxYLVNhLI0fSWu4wr8UON7PIdSGrl86dMS0qXW62mU425nakmpzTXMZO5b9LRf67/Sr/PSry32tkvkVkJ5ZmejrtzPSdDzSoEsf7/RrHB1Ti+GAGd0WjlVT6vYxWUhlcoD1kV0k9bN14Dwv5iB/1e1RFv8f8qt/jKvo94SX9nrTT7yk/GrdexbgNfjXuaRXjnvGScc/aGfdcKDbSYoAeF2G5MWSNtPi8H318QcXHF63bwdZ6g4GCgscbafKluNvBL/vxQLyiciBe9WvBfE2lYL7upYL5hl3BfDPuVvFb1qUTSRRSTasdvVX8tnVrU5PvxN3afNePwr4XcjjSxvt+lfUDFVk/9JKsH9nJuil2S/NjP4r3iVPxNvtVvC0q4m31knif2on3WcgaE/lzP4r3hVPxvvTj3n3ldO++9mux+kalWH3rpWL1nV2x+j6UNOvZtthVwXY/uviDUxd/DMXP4ZJ63FX5U8gam50c8mfzvlFIaNX+Dw==

  1. Screenshot OR error code
    N/A

  2. Expected behavior
    The trap monster should’ve been put face-down, and as a result into one of the S/T zones, and I should’ve been able to summon the Subterror monster with Fiendess’ effect.

It works as intended. You have 5 monsters occupying all main monster zones. The effect of Subterror Fiendess is simultaneous (and if you do). Hence, even after the Trap Monster is flipped face-down and returned to the S/T, the monster zone is still considered occupied at the time of the activation. Hence, there is no unoccupied main monster zone for the Special Summon of the Subterror from hand/GY.

Please also refer to Rokket Tracer vs Dilingerous Dragon and similar rulings here: