Movement control lock up bug
I’ve noticed the same problem happening as well although it has been happening on rare occasions since release. The problem seems to be that your character slips slightly under the floor as you can see part of your feet are no longer visible. This prevents you from moving in any way and the only solution I have found it to either teleport to a way point or log out and back in again.
A very similar problem can also happen if you happen to be standing next to an item which explodes, in this case you can end up trapped in the exploded item debris and the only solutions are way point or wait for the item to reset.