Bottom lane Outer Tower not attacking minions
It happened to me in this game where I was playing Sona with MF. When we first realized the tower was not attacking it was shortly after dragging a large wave of minions above the tower below tri-brush. I have not done any testing on trying to replicate this bug in any way shape or form but this was a really bizarre and game breaking bug that could highly impact other games that are played. Sorry for not being too much help with this post but hopefully someone who reads this can do a more thorough investigation and figure out why this happened.