Removed and re-set the GPU and its power cable (though the power cable led was on so I doubt it had anything to do with it) and it went away.
Then it happened again, so I did the same thing.
Then it happened again today, and it fixed itself with a cold boot.
Never happened on my previous MB (x370 gaming k5) and gaming works fine, so I'm pretty sure this is just another initialization issue with the MB.
Not that big of a deal compared to everything else, but if anyone working on the new Bios' is checkign this thread it's worth mentioning in case it can be fixed.
Look like we got same issue... gpu error beep code when shut down...have to reset psu to boot not cmos,cmos is ok...
When booted can restart all day no problem but dont shut down... its annoying lol