Machina Fortress couldn't be special summoned by discarding himself and Desperado Barrel Dragon.]
Bug reproduction steps
Have Machina Fortress and Desperado Barrel Dragon in hand. Use Machina Fortress to discard itself and Desperado Barrel Dragon to Special Summon itself. This would normally work in Duel Links, but this is not the case in Omega.]
your replay code
Machina Fortress wasn't able to be special summoned.]
you don’t discard both Machina Fortress and Desperado Barrel Dragon, the correct way to do it is; discard Desperado Barrel Dragon then click on the confirm button in the upper right of the screen.
There’s no reason to NOT be able to special summon Machina Fortress by discarding himself and another machine. I don’t see why it wouldn’t allow that?
Desperado Barrel is LVL 8, you can’t discard more than what’s necessary for the special summoning of Machina Fortress