I-Bond Amended Tax Return Help

Hi all,

So I completely forgot that I had sold two I-bonds in 2025. I have put the 1099-INTs into FreeTaxUSA and it now says that I owe $981 in additional federal taxes. The total amount of interest on the bonds (there were two) was $3532.

The tax amount seems quite high.

Can anyone help explain what is going on?

Numbers including the I-Bond interest:
Taxable Income in 2025: $249,689
Taxes Due: $47,042
Paid: $45,679 (Thus leaving me the $981)

State: (I discovered it went into Box 1 and when moved into Box 3, state taxes went away. Question stands for Federal taxes.)