Annoying auto glitch?

idk if its a glitch but it happens so often and has happened for like years, whenever someone starts an auto animation, it doesnt mean they should finish it.

Today a Rengar killed me 5 times after being like 5-6 teemos away, i condemned him away 4 times and he would fly back but still get the auto damage, then the other time i went invisible and hit the blast cone, he was near red and i was in baron pit, and the auto killed me.