Several bugs with Illaoi make it nearly impossible to play against her currently.
The hitbox of her Tentacle slams (P,Q,W,R) is considerably larger than the telegraph zone indicates. Dodging narrowly becomes impossible that way.
Same applies to her E, the visuals of the spell are smaller than the actual hitbox making dodging much harder than it should be.
Her passive also has 2 gamebreaking bugs, when Mordekaiser uses his ult on illaoi the tentacles she spawned sometimes carry over into the death realm.
And her tentacles continue their attack even when they have been destroyed. When a tentacle starts a slam attack but gets destroyed during the windup it will still perform its attack. Not only that but it will no longer have an indicator where it will hit and be completely invisible. Killing her tentacles makes them stronger. That definitely needs to be fixed.