I think i know why GA doesn't work sometimes

Played a game today and an enemy kayle didn't revive after GA. Thinking back on it after the game i realized my volibear had red buff and i think that may have caused GA to not revive. So i went back and looked at an old plays a friend showed me about how his GA bugged and there was a red buff there too. I think that grievous wounds from red buff/morellos might stop the GA from setting a units health at 1000 and instead either set it at 0 instantly killing the unit or setting at like 1 and having the burn from the item kill them.

IDK if this is a bug or intentional but i feel like its a bug.