I initially noticed this when attempting to load some avatars, I would appear as a solid black version of the robot avatar in a t-pose with a pink square on my chest. Later on I joined an instance with some friends, and noticed one of them looked similar, but not in the t-pose (was on PCVR), but the spot on the chest was the avatar image for their fallback avatar.

Also looking down I appeared as a textured sphere, but couldn't make it out. In the mirror and camera thought was as described above.

Was on iPhone 14.