Cannot preview customized screen even if I delete it and start from a clean copy

I am posting this in case anyone ever has the same issue, they will know how to fix it.

I have a customized version of AP301000 in R2020R2 Build 20.207.0012.  The page publishes and works fine.

In the project editor, on my custom field, I entered a LabelWidth with a value of “M”.  This caused the page to error.  I unticked the checkbox on the LabelWidth propery.  The value [RESET] was automatically filled into the value field.  I saved the change and tried to preview and I got this error

Steps to try to get rid of the error:

1. unpublished all
2. deleted the screen from the customization
3. published the project
4. restarted the application
5. cleared cookies from the browser
6. added the screen back into the project with no changes.
7. clicked preview changes and I still get the error.

I tried this in a different browser, same thing occurs.

I also verified that after deleting and unpublishing, in the project editor, there was NO reference to AP301000 anywhere.  I checked this by going to File - Edit Project XML and by going to File - Edit Project Items.