Is there a specific order that should be adhered to when setting output processors? Sometimes they don't seem to work.

I've noticed the same. I believe the processors get executed in the order they appear in the parameters, and they're not aware of one another. So if Use Relative Paths is first, it sets the paths, then Copy All Assets uses that path, which is the one now stored in the usd file, as the target for the copy, but they're already in that location.

BryanRay
I've noticed the same. I believe the processors get executed in the order they appear in the parameters, and they're not aware of one another. So if Use Relative Paths is first, it sets the paths, then Copy All Assets uses that path, which is the one now stored in the usd file, as the target for the copy, but they're already in that location.

I've found I have to put 'Copy All Assets to Referencing Layer Directory' first in the stack.