This happened to me twice so far, both times when spawning for warmup as defender on Underground. Basically my view point was offset back from where it should have been so it looked at first as if I was spawning inside / on top of another player, but when I moved it was clear that I was somewhere between a 1st and 3rd person view point, seeing part of my own model from the inside. In both cases the view point returned to where it should have been after a few seconds.
Playing as Fragger’s backpack:
Being inside Rhino’s head:



