Illaoi Bugs
Most of these have been with her since she went live.
W interaction with displacements and slows. Fight a good Darius to see them in action.
If he pulls you while you have W active it will not let you attack some times and you have to wait for the buff Icon to fall off (5-6s) before you can W again. Could be that its Interrupted (tho it should not ever be) but the buff does not get removed.
Have Darius slow you (the 90%+ slow) and Try and W, the leap range or speed is also slowed so you cant use it well.
This all happens with the new Pyke too. His Stun and his Pull will mess up her W.
Fight Garen while he spins and try and W him. His hit box size changes or something so he is VERY hard to target with W.
E interaction with most champs
Any projectile that is a object will block her E. Ekkos Q Jinx Rocket Ahri Q Old Swains Q bird
Also if Garen is spinning it will block her E some times.
New Pyke can E through it and not get spirit pulled even if he is right in it. Could be most dashes also do this.
Illaoi could be a top tier champ but she has so many bugs with her kit it hamstrings her.