Hi,
I wanted to report a bug that occurred to me a couple of times: sometimes my Beedril (who is level 12 and has only Fury Attack) will perform a "Struggle" move when i click on Fury Attack. I tried to understand why it happens to help you, but it seems that it happens in random circumstances. If the battle ends the move will return normal in the next one. Next time it'll happen i'll make some test to help you and i'll add them in this topic.