I made regular "quarterly" payments, one in each April, June, September, and January (2021). Form 2210 Line 19 Column (a) should sum all estimated payments through July 15, but it only picks up the April payment. Column (b) is not used for 2020. TT probably migrated 2019 code, simply removing column (b) calculations rather than combining them into column (a). Your workaround - combining my April and June payments into a single entry - works, ie, it forces the correct result, but I would rather see TT fix the problem in the software. Anyone who makes estimated tax payments and uses this form to calculate an underpayment penalty may unwittingly overpay the penalty as a result of this issue.
