Ugh, I just discovered the same issue as well--just received a payoff of the balance on my installment sale that was working properly in TurboTax from the sale year (2012) to 2018, and then poof, since 2019, it appears 6252 has failed to generate. I trusted this software to do its job, so it's only now, as I was going back to figure out what's been reported, that I realized it never created 6252 for 2019, 2020, nor 2021! Interest does seem to be flowing properly, just not the principal.
Does this mean I need to go back and amend those 3 years using the hack provided above (entering a new installment sale)? How annoying!
