TurboTax Deluxe 2021 (download) on 1040/1040SR Worksheet, line 12b has a possible bug

[schernof]

on 1040/1040SR Worksheet, line 12bPossible line 12b bug
Line 12b is auto filled in as $300, even though I entered $500 for cash donations (somewhere else) made with 5 repeated $100 donations. The $300 is flagged as an unacceptable value, even though I'm married filing jointly. I think it should be $500 in my case since I'm allowed up to $600 as a married filing jointly.

[DoninGA]

To remove the error I went into Forms mode and deleted the Charitable Organization Worksheet.  Then on the Form 1040 Worksheet for Line 12b removed the $300 amount so Line 12b is now blank (empty).

Going back to Step-by-Step I completed the Deductions & Credits section without entering anything for a charitable donation and click on Done with Deductions.  Continuing through the screens until landing on the screen labeled Charitable Cash Contributions under Cares Act, I entered $600.  Continued through Final Review without error.