Morgana Q binding with a larger hitbox than it should be.
Posted this on twitter to RiotSupport and was told to do it here as well. As you can see from a photo, despite avoiding Morgana's Q i still got rooted as the hitbox was larger than it should be. Unfortunate that this was just one of too many cases i've witnessed but never pushed myself to provide some evidence.
As a Riven player, i've also witnessed more than enough scenarios where i would just before a dash,get hit by her Q and drag myself along with her stun for the full duration of my dash.