Bjersgen's Zilean bombs in tsm vs imt game 3

It happened numerous times during that game where targets would come out of stasis or tp and would be able to flash out of the zil bombs that were already placed directly at their feet. Shouldn't the bombs attach and stun the moment the target appears on top of them ? What is going on here ?? I've also had numerous occasions of this happen in my games as well as a bug where the bombs attach and the stun animation goes off but the target is not stunned. Can I get a rioters response on the matter please ?