So, I’m assuming this is a bug in both testlive and live, as it’s a fairly obscure trigger for this bug. Simply out you lose control of your character/ get stuck in vanity mode, but with the UI showing.
To trigger this bug, Aim your reticle at a chair, or bench, press v to enter vanity mode [unless you rebound your keys, then press whatever you set it to.] now, the game still thinks your character is looking at the chair, you can just sit in the chair, and this lets you have vanity controls while in a chair, clever idea I thought of to get that, for a UI free screenshot while sitting.
However toggling vanity mode, or really interacting with anything is disabled while sitting. When you then go to move to get up from the chair, your UI is restored, but your controls are still as if you were in vanity mode, and to top that all off, your ability to interact with anything is disabled as if you were still in the chair. Effectively losing control of your character until you exit and re enter the game.