I have recently stumbled upon a very strange issue and it has been quite a big annoyance to me while trying to make and test a shader. It seems that an older version of your avatar is loaded rather than the newest version when going to a different world.
The version of your avatar that is loaded looks like it is the most recent version from when you launched the game. This is not a local issue, either. Others were seeing the old version of my avatar as well. Switching from said avatar and back fixes the problem. This would seem to be some sort of caching issue, but I am unsure.
Steps to reproduce:
  1. Login to VRC
  2. Update current avatar
  3. Switch out and back in to see your changes
  4. Go to a different world
Once you are in a different world an older version of your avatar will be loaded.