It is a bug. There were two other discussions where a TurboTax "expert" said a fix to the bug was going to be released April 8 (links below). But after the release, I discovered and reported it was only partially fixed, which means it wasn't "fixed". Of course, after that, the "expert" was no where to be found. So I tried to manually enter what I thought were the correct QBI entries while entering my K-1's. But then I ran into the same problem you did during the final review portion and could not figure out what Schedule E fields they were talking about. I spent a couple hours filling in a field here and there, then seeing how the resulting Schedule E would look, to figure out which fields corresponded to which in the form. Every time I'd get the error, and TurboTax would say my options were either fix the fields or submit a paper return. So I gave up and went back to leaving the incorrect data that TurboTax initially populated. The resulting QBI loss carryover in the Schedule E looked okay and my return was accepted, but I know there's wrong data in there, but I got tired of messing with it and nobody from TurboTax chimed in.
https://ttlc.intuit.com/community/taxes/discussion/qbi-carryforward/00/2092446
https://ttlc.intuit.com/community/taxes/discussion/potential-bug-qbi-carryover-loss-not-populating-p...
