I was told to get a screenshot of the bug but I already left the battle out of sheer disappointment lol. This happened to me twice already for the E4 battle... its where the opposing mon would use U-Turn and it would completely bug out the battle by not registering the enemy pokemon as "there". I would try to attack but it would just say "But it Failed" after any attack that I press. The enemy mon wouldn't even attack back either, I was just fighting nothing. I'm okay with this happening with an NPC gym fight since its 15 minutes, but the E4 battles have a cooldown of 1 fucking hour.