Sylas Unable to Attack for Over 1 Full Second After E into Minions [GAMEPLAY]

Several times when I've played Sylas , if Abscond (E) into a cluster of minions, enemy or friendly, I become unable to move or auto attack for between 1 and 2 seconds. Trying to capture video to show, but it doesn't happen EVERY time. Even when I dash into a group of enemy minions, I'm unable to auto attack for a second or so, so I'm confident I'm not just being creep blocked and out of range of a target to auto attack.

It's most frustrating when it happens while I'm fighting an enemy champion. It's as though I'm stunned, completely CC'd when indeed I have not been by anything other than this glitch. I've tried casting spells, auto attacking, etc. Nothing for nearly 2 seconds.