I'm so sorry this issue has not been fixed (I am the original poster). I feel your pain and the hours of aggravation. One would think TT would have seen this, after such specificity and the IRS clearly permitting e-file if Form 1310 has been submitted.
I paper filed (with the extension) and haven't heard anything. His final returns sits in stacks of other 2020 returns and amended returns unopened with millions of other paper filings. It could be another year before I can finally close the checking account. Had TT allowed e-filing of returns with this issue, I'd be wrapping up soon. Filing returns for the one you lost is excruciating, and again, it's disappointing that all my words and effort meant nothing to TT.
Now, I'm preparing the estate's (and my) 2021 returns, including Form 1041, which requires the TT Business version. Also annoying. Kind of expecting to be my last year using TT, esp. given their lack of responsiveness to a known and well explained issue.