Thank you, that helped me correct the problem.

I had the same problem and nothing I did through the review process worked. I ended up having to go back and add enough charitable gifts under the itemize deductions option so my total was over the $300 limit. The problem was that I had never been prompted to enter them since I qualified for the standard deduction. At least... I think that's what finally stopped the review trigger.

Dear Turbotax:
In the Desktop 2020 Premier software using the Interview Method I skipped Schedule A (including Charity Donations) since I was taking the Standard Deduction. I was later presented with the Affordable Cares Act (ACA) option to deduct up to $300 cash. I estimated an amount and entered it. When I later went back to try to change it I could not find any link or reference to that ACA Contribution Deduction.

I tried going to the Forms to see what the Data Source was for it so that I could find it that way, but the Data Source option was greyed out. I tried to jump back into the Interview Method blindly to find it and when I located the first ACA question it reset all the actual data that I had entered on my rebates to a default value.
There has to be a better way to access this ACA info and each of its sub-components directly as well as coordinate it with Schedule A where it showed that I had no Charity entry (since I had not even started that Schedule). How to we get back to the ACA Charity value we entered and change it without redoing all the other related ACA info and why is there no reference to the ACA section in any link for direct access?
Thank You For Your Anticipated Response.

The workaround is to delete the $300 in the error check. Then go back to Deductions & Credits and enter the contribution there, in the Donations to Charity topic. Then click Done with Donations and proceed through the screens until you get to the screen that tells you that TurboTax has added in the contribution.

 The contribution will be back on Form 1040 line 10b, but it won't be flagged as an error. It only gets flagged if you enter it when prompted after you finish Deductions & Credits and the software tells you that you are getting the standard deduction. It will not get flagged if you enter it in Donations to Charity.

Please try the following workaround: 

1. Delete the $300 in the error check.
2. Then go back to Deductions & Credits and enter the contribution there, in the Donations to Charity topic.
3. Click Done with Donations and proceed through the screens until you get to the screen that tells you that TurboTax has added in the contribution.

The contribution should appear on Form 1040 line 10b.

How the CARES act changes deducting charitable contributions made in 2020

Previously, charitable contributions could only be deducted if taxpayers itemized their deductions.

However, taxpayers who don't itemize deductions may take a charitable deduction of up to $300 for cash contributions made in 2020 to qualifying organizations. For the purposes of this deduction, qualifying organizations are those that are religious, charitable, educational, scientific or literary in purpose. The law changed in this area due to the Coronavirus Aid, Relief, and Economic Security Act.

Keep in mind, it is very important to keep records of your charitable contributions.  If the IRS asks about them later, they will be denied if you don't have a record, receipt, letter, etc.

@Poolmon