It’s hard to tell because it’s during pvp, but I believe the culprit is taunt.
Since the recent update, I sometimes find myself unable to move for several seconds, as though I’m immobilized, even though I have no conditions or control effects on me anymore. I can still cast skills but cannot turn or move until I’m hit by a fear or knockback, after which I can move freely. The first time it happened, I was stuck facing an enemy bristleback. A moment ago it happened while I was defending my lord in stronghold. I can’t give many more details than this, but it for sure always happens after some kind of assortment of conditions or control effects.