Project Setting may not save if you have an additional custom 'title' reference Tag. The capitalized 'Title' Tag is the default field to which the titles of your references should be associated. This duplicate 'title' field (with the lowercase 't') prevents the saving of your Project Settings.
To resolve this issue:
- Go to References > Formats > Delete fields.
- Find your 'title' field.
- Select 'title' and click Delete checked Tags at the bottom of the screen.
- Go to Project > Project Settings. Make your desired changes and click Submit.
- Verify that your changes were saved.