More often than I'd like to admit, I run into the same little issue that usually takes me more than a couple of minutes to figure out. In this specific case, the small issue that I'm talking about is map views that I create not showing all the markers I think they should.
When creating map views using either GMap or Mapstraction, the part that I overlook is forgetting to pump up the "Items to display" value. By default, Views sets this value to 10 - but, more likely than not, your map is going to show more than 10 nodes.
I've run myself in circles several times trying to find the bug - often thinking the geocoding isn't working - only to do a head-smack when I see the easy fix of increasing the "Items to display" value to about twice what I think it should be.