When you start your federal tax return the program enters the Recovery Rebate Credit on your Form 1040 Line 30 for the amount of credit you are eligible to receive. After you have entered the amount of the 3rd stimulus payment you did receive, the credit is removed from Line 30. You cannot receive the same payment twice.
This is reflected in the Refund/Taxes owed indicator.
What you may not realize is that as soon as you began to prepare your tax return, the software was giving you the $1400 and it was shown on that "refund monitor" -----but when you entered that you received it already, the software had to reconcile the payment you received, You cannot get it twice---so it looked to you like you "lost" $1400. You did not lose it---you just cannot receive it twice.
You must enter the amount that you received. The IRS cross checks for the stimulus if you put it on line 30. They know if you received it; if you put it there again they will reduce your refund.
Yes, it will definitely affect your tax return. If you never received the third economic impact payment (3EIP), or stimulus, then you would still be entitled to that because it was based on and reconciled with your 2021 tax return.
If you already received the $1,400 (for each spouse and dependent) on your 2021 tax return, then you will enter the amount you received and the result will be any amount remaining which may be zero.
If you did not receive the 3EIP before filing your 2021 tax return then it would be added as a payment on your tax return and reduce any tax balance due or increase any refund. In your case it appears you have a balance due if you already received this payment previously.