Specifically, just looses the ability to "rotate" character. Freelook still works, inventory mouse still works, etc.

I've been hosting games from the in-game option (so not as a dedicated server).
When another player dies, for the duration they're in the respawn screen, I would be unable to rotate/aim my character.
Still retained WASD movement, and holding down alt to freelook would work. Just had zero ability to change where my character was aiming his gun.

Next time I host again, I'll record the whole play session and I'll include any game logs.