Fiora bug I just witnessed.

Playing in a normal blind with two friends, and this was seemingly unbeatable. At first I attributed her low death rate to just a high level of skill in comparison. Although she was a very good player, I noticed a particular incident that made me question the status of her playability.

She had about 1/4 health (out of 2500~) when a friend of mine dunked on her. I was standing in lane with him, trying to help when I watched it. Her health actually went up to half for literally no reason. She didn't pop hydra, parry, anything. It just went boom, here's a quarter health. Definitely lost the game due to this and would just like to make sure it doesn't give an unfair edge to other players.

Unfortunately I really don't understand how people 'screenshot' their games so I have never done that. So, could one of the fine Rioters please look into this? Thanks in advance!