Poppy's E interaction with any of Riven's dashes (Q & E - skills)
Poppy's E doesn't seems to interact correctly with Riven's Q & E skills, they neither dislocate Riven's position in anyway if Riven in both cases. Poppy's E tends to usually work against other similar skills in the way that they atleast dislocate the enemy in some manner.
I haven't tested it yet if it's 100% of the times, but it happens most of the times.
Happened in a 5v5 normal Blind-Pick game on the Summoner's Rift