As of the VRChat beta build 1385, mesh renderers behave differently than previous updates. In the past I normally use a small quad with big bounds to reproject what I have on my avatar's camera into the corner of the screen. It's if as though the mesh is getting culled from my POV even though I have Dynamic Occlusion disabled on the mesh. Either the player's POV is deliberately occluding the small mesh or the bounds of the non skinned mesh are not working properly. the image in the corner will only pop up if:
  • you are previewing the model in the main menu
  • the world has your model duplicated and you can look at it (possibly in mirrors but the shader in this case has a parameter to exclude mirrors)
  • your avatar is in an obscure position
If the mesh is a skinned mesh renderer with a similar bounding box the result will replicate what's on top of the first image, otherwise if it's not a skinned mesh renderer it will result in the bottom of the first image.