Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
So I went and looked into it. This seems to be an PE bug.
The choice Items do not let the move struggle be used if another move is locked. This will also prevent a choiced Pokémon from struggling once it hits 0 pp.
So the solution here is to add a struggle check:
In the Script...