When trying to use the card “Junk Converter”'s effect in the graveyard to special summon a Tuner, the monster is bugged. The prompt “?:-1 attempt to perform arithmetic on a nil value” pops up. "This monster can be used as synchro material, but it cannot leave the field. This inability to leave the field can cause it to be used as the Tuner for multiple Synchro monsters, and nothing I have done can remove it.
Bug reproduction steps
Discard Junk Converter from your hand to activate its effect, adding Junk Synchron.
Normal Summon Junk Synchron, summoning Junk Converter via Synchron’s effect.
Tune Synchron and Converter into any level 5, I have used Hyper Librarian.
Activate Converter’s effect, targeting any tuner in the GY.
The summoned monster should have the popup and the afformentioned bug.
Screenshot OR error code
The Stardust Synchron on the field here is bugged, as the next picture shows me using it as material to summon Stardust Charge Warrior, but the Synchron stays on the field.
I planned here for 2 more screenshots showing that I was able to summon Stardust Charge Warrior and Satellite Warrior using Stardust Synchron, but I made an account here to make this post and I am unable to place 2+ images here.
What should happen is any attempt to use the monster summoned by Converter’s effect as synchro material should be sent to the GY like any other Synchro Material.