Deductions & credits

Hi, I have trouble of Foreign Earned Income on 2021 Turbo Tax.  I finished all tax entries first except "Foreign Earned Income" and I have some refund from Federal as indicated by TurboTax, however, when I entered the amount of earned income the "Federal Refund" dropped $2500.  Although the Foreign Earned Income Exclusion says I'm qualified for the exclusion but the refund amount never goes back to amount before.  I tried many times using different options but it always reduces the refund as soon as I entered the Foreign Earned Income.  Is this a bug in TT or something I did wrong?   Thanks in advance for any help!