https://github.com/pret/pokeemerald/blob/95aa41f0d42e1089e4bb082a614cab02419ad701/src/party_menu.c#L4746 this is UB, what it is doing is modifying learnMoveState. that might mean that the function was not matched correctly
pokeemerald/src/party_menu.c
Line 4746 in 95aa41f