D16944 changed fulltext search to conduct the fulltext limit first, capping results at 1000, before filtering for other criteria. This can lead to missing results.
Take, for example, a query for "daemon" -- I've limited it down to other criteria that I perhaps remember. It finds no results because the particular task isn't in the special 1000 found by full-text search.
Adding an additional word makes it find results. It is counter-intuitive that adding constraints would broaden the result set. The logic of "Better to return quickly and let the user refine their results" from D16944 does not make sense if the user sees no results, or at least not the result they are expecting -- no user will intuitively assume they need to further refine their query from such a results page.