After you file

Yes, your Bond Market Discount is reported as Interest, on Schedule B.

Market discount recognized as income, whether currently or when you sell/redeem, will be added to the basis of your bond when you are figuring gain or loss.  If you elect to currently include in income the market discount on a bond, increase the basis of the bond by the market discount that has been included in income for that bond. 

You may need to delete these entries from your imported data and enter them manually, if you can't edit the Cost Basis in the import.

Market discount is the difference between what you paid for a bond, and the maturity redemption price.  If you bought a $1000 bond for $950, your market discount is $50.  This discount must be included in your income, as interest, either over the period you own the bond, or when it is sold.  In box 1f your broker is reporting the accrued amount of discount over the time you held the bond. TT will show it as interest income on Sch B (look and see if it's on that form), and then subtract the same amount from your gain on the sale (Form 8949), since it's already been reported elsewhere. 

If you enter these transactions manually in the 1099-B section, enter the amount from Box 1f as a negative number in the Total adjustments to gain (or loss) and Code D as the adjustment code.

Code D lets the IRS know the gain is being adjusted for an accrued market discount. The adjustment amount will be reported as interest income on your tax return.

If it does not carry to Schedule B automatically, you will have to carry it over by entering the amount in the Capital Gains Adjustments Worksheet in Forms mode. The Accrued interest to schedule B in Part IV should be highlighted. Enter the adjustment amount here.

What is happening is that you are recognizing less of a gain on this sale because a portion of the gain is being reported as interest.

Here's detailed info in this Guide to Investment Bonds. 

@Clancampbell