Look at the indicator.  Does it say Federal Tax Due or Federal Tax Refund?

It says refund. Clearly and in green. Depending on how much I put down for the stimulus I received, it changes my refund amount. So if my refund is $2,500, and I say I received $600 stimulus, it changes my refund to $1900. If I go back and say I got $0, my refund goes back to $2,500. If I go back and say I received $1 stimulus, my refund changes to $2,499. This is deliberately making me pay for my stimulus, and every article and even on the Turbo Tax website, states that this should not be the case.

It is the same with my return.   Takes me from getting a refund to owing federal tax.  Also not sure why we have to claim the 2nd stimulus amount on 2020 return when we didn't get it until 2021.  Can you answer this TurboTax????

The IRS specifically asks for you to enter the amounts of stimulus payment 1 and stimulus payment 2 in the

computation of the Recovery Rebate Credit.  Many of us received the second payment after December 31.

Before you enter the amount of the stimulus payments at the screen Did you get a stimulus payment?, you have been given the full Recovery Rebate Credit (the equivalent of the two stimulus payments).   This can be found on line 30 of the 2020 Federal tax return.  At this point, this is an 'incomplete' Recovery Rebate Credit.

You can see this on the screen Great news! You qualify for the stimulus credit.  The amount is displayed in the center of the page.

After you enter stimulus payment 1 and stimulus payment 2, the credit is offset by the stimulus payments and the 'incomplete' Rebate Recovery Credit is reduced or eliminated.

See this TurboTax Help.

You need to enter it to see if you qualify for any more and so Turbo Tax doesn't give it to you again.  The Stimulus Checks are really based on your 2020 return we are filing in 2021.  So any amount you already got will be reconciled on your 2020 return line 30.  If you didn't get a Stimulus Check (and qualify) or you qualify for more it will be added to your 2020 return.  But the good news is if they paid you too much they won't take it back.

Your 2020 return starts out by assuming you didn't get any Stimulus payments so it gives you credit for the full amount.  Then near the end you enter how much you actually got so it only gives you the difference if any.  So you don't get it again