"Exempt US Bond Income" is the other way around - US Obligations that are Federally exempt but VA taxable - I don't have access to VA online only desktop but the help popup for this line refers to "income from interest or dividends on US obligations (bonds) or securities that is EXEMPT from federal taxes, you'll need to add that income, minus expenses, to your VA state return"
I'm not sure offhand what type of bond this would be as munis are not "US obligations" and muni additions for issues taxable in VA are covered automatically from the Fed return 1099 data.
The only scenario I've encountered needing special handling for Treasuries has been the treatment of Accrued Market Discount on discounted Treasury Notes reported on 1099-B which gets added to ordinary income but does not get subtracted automatically from state taxes (and there are different interpretations of this state by state).
Anyway - don't fill that in, it should be coming automatically from your 1099s. Once you've specified the US Gov Obligation amount on the 1099-DIV that should be flowing automatically as a subtraction to 760 Line 7. What do you see on that line? If you don't see anything then I would go back over the 1099-DIV.
