I don't use import but not surprised that it can't do this calculation as often the supplemental tax info needed to make this calculation is not in the statement, I had to go to Blackrock to get the % for TFDXX (link below).
In the desktop you should be able to go in and update the 1099 that was created by the import, either thru EasyStep painful UI but scroll around to find and edit it, then after the main screen with all the 1099-DIV box details, click continue and you will get some interview questions including whether some of it was US Gov % and you can provide the $ figure. Or, go into Forms mode and find the 1099-DIV and there is a space for the $ amount immediately under Box 1a.
You'll need this letter from Blackrock which gives you the % and multiply the amount of dividends from this fund to get the $ amount to enter
https://www.blackrock.com/cash/literature/shareholder-letters/blf-taxable-tax-exempt-tax-letter.pdf
Once this is input on the 1099-DIV you should see that flow thru to your state return as a subtraction to your taxable income.
