Are you using the latest UAD drivers?
They are pretty buggy and haven't been updated in awhile, I have a similar problem with my speakers being detected as a really high ohm so they get distorted and headphones get detected as having a lower ohm than they should.
I would try installing the old non UAD drivers and see if that fixes your issue or wait for asus to fix the drivers :rolleyes: (Don't hold your breath)