I just called TurboTax Support and the wording on the Social Security worksheet seems to be confusing or incomplete. It (also?) includes line 10b of your 1040-SR. In 2020, you are allowed to take a $300 deduction for charitable contributions even if you take the standard deduction. That is what showed up in my case. The $300 is actually reducing the amount from line 5 on the worksheet. Hope this helps.
