There is an easily replicable bug that lets you attack enemy champions under tower without grabbing tower aggro, pointed out by this Reddit thread.
As you can see in the video, attacking a champion while the tower is changing aggro makes it so that the tower doesn’t aggro you as it should.
This is obviously a bad bug to have around, as players losing lane typically need to hide under their tower to avoid enemy baddies. While this bug might not be as easy to replicate in real games (since you shouldn’t just stand and wait under enemy tower), it still is pretty dang bad.
Life in the top lane or mid lane is much more scary with this bug around, since towers don’t exactly feel safe anymore.
There has been no update on this from Riot Games about fixes, but we can probably expect it to be patched soon.
This article will be updated as more information becomes available.