@JohnB5677
Thank you! Your suggestion works.
Now Line 11 on my Schedule A says that I have made no charitable deductions, and Line 12b on my 1040 says I made $600 in charitable deductions. I note that the IRS instructions for Form 1040 state that people taking the standard deduction don't need to provide a Schedule A or supporting documents. Your instructions make sense in light of that guidance.
I still maintain that there is a defect in Turbo Tax. At the very least, Turbo Tax should correctly handle the case where users key in charitable contributions as part of the normal data entry process, are told that the standard deduction works best for them, and then take the CARES Act deduction.
