Search always returns "No results were found"

We've recently been working with upgrading to Sugar 7.6. One of the main problems is that the Search (Global) at the top left does not ever return any results.

  • The list view search works fine.
  • Elasticsearch works correctly when curl'ing to it.
  • I have tested the Search options in the Admin, and subsequently run an index using the scheduler.
  • I still get an empty array as a response for every single query in this input.

Is there anything else I can try?

I know for a fact that my data exists, for example:

I get plenty of records with %test% in listview, but never any in the global search.