So first time I noticed this bug is when a Caitlyn in my team used her ult on an enemy who was just close to be visable. Right when Caits ult casted the enemy champ went invisable and the ult didn do any damage BUT went on CD...
Exact same just happend while I was playing Annie... I chased an enemy and casted my Q which would hvae killed him. The animation came, also it went on CD but the enemy didnt recieve any damage.
As it seems ot happen with nearly all abilities it should be fixed asap... if anyone had similar issues just post it.
But this needs to be fixed!