Thanks, that explains it somewhat. The date matching is not an entirely bad idea, but it has its shortcomings.
Particularly with older ancestors, DOB and DOD are often unknown. There are also frequently conflicting dates from various sources.
Two of the results from the general search have no dates. The magnifier does not find these. I also wonder whether the search algorithm is accepting "near" dates as possible matches. I do think it should show results for near dates and no dates.