Retirement tax questions

Bottom line you may need to get the 1099r reissued or you may have a subtle TT bug. I'd start by calling your 401k provider and asking why the IRA/Simple box was checked for a 401k. (see below).

Was the 401k a designated Roth 401k or a traditional 401k?

Do you know if the 401k was a "deemed IRA" (see page 3 of the instructions below)?

Is this the error you get? (This is from the desktop TT not the online)

You might try looking at Page 4 of the 1099r instructions ("Direct Rollover").

https://www.irs.gov/pub/irs-prior/i1099r--2021.pdf

It is also possible that you could get away with unchecking the "IRA/Simple box" and seeing if that works. While there is a danger that something won't be calculated perfectly in that case, if this was a direct rollover, and doing so causes TT to treat it properly (i.e. not as a taxable distribution), you might be ok. I can't guarantee though.