Mordekaiser ult (theres a lot of these lol)

If you're inside Mord ult, and attempt to kite him around there is a bug in which you will simply be rooted in place unable to perform any actions. Went back through replay & even paused it to look for a debuff. There was nothing I was simply rooted in place near, but not on, edge of his zone & was completely unable to move or perform any actions (I was fio if that matters)