So I was playing singed and tried to flip warwick while he was Q-ing me, I didn't know before that, that he can't be displaced but the ability as a whole was cancelled. I had Rylai and deathfire touch neither of which applied and all the damage was ignored.
Attached to this is a video of the bug.
So, it looks like your ability did do damage to WW. Not very much, but it did do damage. You can see WW HP drop after you hit him with fling, then he gets the health back upon killing you. Also note that the damage he took was not from poison, because he was not poisoned at this point. He had virtually the same HP at the beginning and end of the interaction because of the heal he got from your death. (presumably life steal items)
As for the poison, of course he didn't get poisoned again until after he kills you. He didn't walk back into poison until after he killed you.
Can 100% confirm this is a glitch with his Q, the same thing happened when I used poppy E into warwick, he should have been stunned into a wall instead he used his Q just right before on another champ, and it came up as cannot be displaced. If this has gone on for a year this is utter bs and needs be fixed, Riot you've been making this game for years and there is no excuse to have bugs like this in the game.
It's an intended mechanic. Warwick cannot be displaced if he latches onto you with his Q. He will also follow you through blinks and dashes.
That said, I think that the duration in which he cannot be displaced should be slightly lowered. I say this as a big Warwick player. There's been a few times this week where I've 'mistimed' my Q but I still didn't get displaced.
