This is a strange one. It is mostly an annoyance since it corrects itself eventually.
During the Serpent fight in vSO, while off tanking the Lamias, the off tank may be sent on a journey under the room. They cannot move and will continue to take damage as if standing still. Eventually, they will pop back to where they were.
First time it happened:
https://www.twitch.tv/videos/243018311[/url[
Second time:
https://www.twitch.tv/videos/248630350
Repro:
1) Run Blood alter. (Sanguine, but morph may not matter).
2) Proc Bahrara's Curse set.
3) Get Blocked by a Lamia to trigger the bug.