Standard (non-Ajax) Search Results of Tags Show No Results

Hello, I have reviewed the Support Forum but did not find anything that addressed this specific issue.

When I set up a search for a single Post Category, I also set it to search tags under Extras (Search category/tag title and Search category/tag description).

But when a search is made on a tag, no results appear in the standard search. However, when I enable Ajax search, searches against a tag do show the expected result (posts that have the tag term but do not contain that term in their content).

Any idea why this would be? I am fairly certain I have the settings set correctly (attached image).

Many thanks for any insight you can provide.

Rob L.