All items on my friends team were removed to see if the issue was that, nope. He switched up his whole team, nope. The only way things worked is if he didn't send out togedemaru first, then it worked. But as soon as he sent it in later on in the fight it had a battle error.

Confirmed! For future reference, when it says a battle error has occured, that usually means a battle error log was generated in your foles, which is usually a very helpful thing to provide when you're reporting a bug :) I was able to easily reproduce this issue and get my own battle error log, so it's not needed this time, but keep it in mind next time :D

Thanks~ Forwarding to Internal!