Latest from dealer: This is an emerging issue with 2020 GTIs. Several have been affected, and the company is working on a new software patch to fix it. There is nothing "mechanically wrong" with the car--it's generating CELs for no reason (hmm....rough idle?). Anyway, the dealer says they want to keep it for another day in the rare case VW has a solution ready in the next 24 hours. Otherwise it'll be rinse and repeat until the fix is ready.
Well that is inspiring. They screwed up the last two model years...on what should be a perfected platform at this point before the MK8 release. I wonder why they decided to change things after 2018.