Searching for "Marc Marquez" this morning did not show any results.  I began to create an entry for this motorcycle road racer and later discovered that he already had an entry.  I noticed that the "Also known as" for English only had a diacritic label "Marc Márquez i Alentà  ".  I then added another "Also known as" Marc Marquez and this resolved the problem of finding the correct original topic.  I merged my erroneous new topic into the original https://www.wikidata.org/wiki/Q40615

Is there an effort already in progress to fix diacritic insensitive search or investigate why it might not be working for logged in English users ?

I only found this older Phabricator issue for Autocomplete during data entry, and not main search: https://phabricator.wikimedia.org/T49114