Flash gets you stuck in ARAM

Hey there,

just had a game with Rengar on the ARAM map and twice after I flashed I just stagnated. I couldn't cast nor move for about half a second. Sure half a second is not much, but if you are in the middle of 5 under a turret, it is. The second flash got me stuck in the enemy Nexus. With q already casted, I still could not attack for said half second.

Anyone the same issue?