Sometimes when playing Riven I end up facing a Poppy, and sometimes, when I e, they also e about a second later and unfailingly it ends with me rubber banding back and getting stunned despite getting out of the way. This is whilst having 45 ms.
This is technically working as intended. Once Poppy's E connects nothing you do can change the position you'll be in after she slams you into a wall. At the end of her E the server puts you where you should be relative to where the ability started. I assume this is because her E is supposed to be carrying you from its start to end and during the duration of the ability you are assumed to have not moved, which is usually true except in the cases where the player being carried reacts just BEFORE the ability begins carrying them.
What this comes down to is really a matter of what ability Riot thinks should win out; Poppy's charge or the opponent's mobility. Considering Poppy's W and how it cancels mobility I think I get what they were going for.
