Then the icon is misleading. On the web version of my observations page, the magnifying glass icon is for searching by species or location.
But now that I look again, it may be searching by location. I noticed in my above example that when I had typed just “m,” it brought up results observed in Villa Magante. At “ma,” these remained. Adding the “c” caused it to find no results. That makes sense if it is searching by location, because I have no observations from places that begin with “mac.”