I believe I have encountered the same issue with TurboTax Premier (Windows), and it's got to be a bug. An IRA distribution that's only partially due to COVID should result in a taxable amount for 2020 that is LESS than the total IRA distribution, but TurboTax is reporting a taxable amount that's HIGHER than the total IRA distribution. (This is for a distribution well under $100k, by the way - others have reported bugs for large distributions.)
The correct formula would be: taxable amount for 2020 = [non-COVID portion] + [1/3 of COVID portion]
The formula they seem to be using is: taxable amount = [entire distribution] + [1/3 of COVID portion]
I verified what was happening by changing back and forth in the interview between "not due to COVID at all", "fully due to COVID", and "partially due to COVID", and each time I switched to forms-view and looked at my 1040. It was very clear that when "partially due to COVID" was selected, TurboTax added 1/3 of the COVID portion to the ENTIRE distribution amount instead of adding it to the non-COVID portion. Here are the numbers (for a distribution of $11,000.. the taxable amount is from line 4b of the 1040..)
None of distribution is due to COVID.. taxable amount, $11000.. correct.
All of distribution is due to COVID... taxable amount, $3667.. correct (rounding error ok)
$6000 of the $11000 distribution is due to COVID... taxable amount, $13000.. WRONG! (s/b $7000)
$10999 of the $11000 distribution due to COVID.. taxable amount $14666.. WRONG! (s/b $3667.33)
If I subsequently tell the interview that all of the distribution is due to COVID, TurboTax corrects itself and restores the correct number ($3667) to the 1040.. so I don't believe I need to delete and re-add my 1099. But I would very much like to have TT properly calculate the taxable amount for a partial COVID-related distribution (I'd edit the forms manually but I don't like overriding calculated numbers and I can't tell where TT is doing the actual math..)
(I uploaded the latest version of TT and re-checked all the above before posting this message. Version number is [phone number removed].) Edited to say: it's NOT a phone number, it's a version number! Lets try again.. 020 dot 000 dot 1690
