Same problem exists in 2021 TT Deuxe download version. I reported the problem to TT, but I don't think they understand the problem. My workaround is to self-limit the carryovers from 2019 to the allowable amount. The TT error is in the Charity Limit 2 worksheet they create. It doesn't correctly input current year donations in Line 8, Used in the Current Year column. Calling TT is a waste of time because they won't let you speak to anyone who is familiar with the form.
