Turbotax bug in 2020 Amend tax return?

[kmorley2021]

I got a corrected year 2020 1099-R for converting after-tax 401(K) to Roth IRA. Box 2(a) increased. I tried to amend the 2020 tax return in 2020 turbotax Premier (desktop version). But if I increase even $1 on box 2(a), I got more than $1000 federal and state tax. It makes no sense. Is this a bug of turbotax?

[Mike9241]

let me put it this way. Unusual but not impossible. We have no access to your return so can't see what's changing.

Make sure that in your amended return any additional tax you paid or refund received with the original return is reflected. If you owed Turbotax does not assume it was paid. if this isn't the reason then you'll have to compare before and after returns and let us know what changed and we may be able to offer an explanation.

look at your 1040s line by line and tell us what lines changed. be sure to also look at schedules 2 and 3

[kmorley2021]

Turbotax asked me whether I have filed. I checked yes. And the amounts in Federal and State went to $0. So it should know that I have paid the taxes I was supposed to paid back then. Then, in the box 2(a) of 1099-R, if I don't change anything, taxes are still $0. But if I add $1 in the box 2(a) amount, immediately the amount went up. And the increase also reflected in the Amended Return Summary. For line 1 Adjusted Gross Income, between the previous AGI and the amended AGI, there is a much bigger difference than the increase of $1. And the amount seems to depend on the total amount in 2(a) instead of the difference. However, if I don't change or go back to previously filed amount in box 2(a), taxes go to $0. Is this a bug in Turbo Tax or are there special tricks to get the numbers right? If this is a bug that there is no way to file amended 1099R correctly with turbotax, I need to find other tax professional soon. The deadline for 2020 amendment is May 17. Only a few days left. Please let me know if there is a way to work around this issue, or if this is a bug that cannot be fixed before May 17, 2024.  Thanks.

[dmertz]

This seems to suggest that you previously reported the rollover as a rollover to a traditional IRA instead of to a Roth IRA, causing the entire box 2a amount to be excluded from line 5b of your originally filed Form 1040.  If the amount originally shown on line 5b is does not include the entire amount from box 2a of your original 2020 Form 1099-R, this is likely what happened, meaning that your originally filed tax return underreported income.

The 3-year statute of limitations on filing applies to a claim for refund.  Your amendment will not be claiming a refund.

[kmorley2021]

I believe have always reported as rolling into Roth IRA. There are 3 years of  corrected 1099-R. All of them behave similarly. I don't think I made a mistake in all 3 years. And in the amendment, I carefully choose rolling into Roth IRA. Is there a way I can check what I had reported in those years? Which line which form?

Also, now when I change box 2(a), the large amount of tax appeared immediately, without me even going to the later steps of choosing whether to Roth IRA or traditional. Since I haven't even gone to that step, that means it's using whatever it had before, correct? If I had chosen traditional in the past, it should still stay as traditional before I get to the later step of choosing Roth IRA,  and don't give me the large sum of taxes immediately. But  TT immediately increases the taxes from 0 to large sum.

Anyhow, where in the form can I find which IRA I filed in the past?

[dmertz]

Examine the original and amended Forms 1040 side-by-side to find how AGI and tax are changing.  You might also need to examine TurboTax's 1099-R forms and 1099-R Summary side-by-side.