Starting today, the Search box no longer returns results.

On one of my wikis, the results page returns "No results found" for terms that clearly are in the wiki.

On another wiki, the result page shows "Showing 1 - 10 of 12 for "<search term>, but the results list is empty.  For example:

This is reflected in the DOM:

Note the lack of entries between comments "Results starts here" and "Results ends here"