Same issue here, backdoor Roth only, no inherited IRA. Been doing it the same way with TT for the last 5 years, this is the first it's ever been an issue.
Comparing 2019 to 2020 the only difference in our Forms 8606 is 15b "qualified disaster contributions" is blank on 2020 and was "0" on 2019. I don't expect that is a distinction that matters here.
It appears to be a bug in TT's XML e-file language submission - I just hope they get it fixed as promised by March 5th, I don't want to deal with the hassle of constantly checking back to see if its fixed.
Seems we have earned ourselves a partial refund or discount for next year (if there is a next year with TT)...
