I suggest you verify the derivation of the total value for DC Schedule I Calculation B line 1.
The DC document '52926_D-40_12.21.21_Final_Rev011122.pdf' from the DC Government site 'otr.cfo.dc.gov/node/1575406' says the following:
SCHEDULE I Additions to and Subtractions from Federal Adjusted Gross Income
Calculation B Instructions
Subtractions from federal adjusted gross income
Line 1 Taxable interest from US Treasury bonds and other obligations.
This interest is included on your federal Forms 1040 or 1040-
SR, Line 2b or 1040-NR, Line 9a. It may be all or part of that
amount, or it may be 0. Also see your federal Form 1099-INT, Line 3.
Without going into personal details, I have reason to believe that TurboTax Premier 2021 as of 2/12/22 is deriving an incorrectly large value for this line resulting in an incorrectly low value for tax due.