Lately an old problem with map drawing has resurfaced on my system. While zooming in to find POIs, sometimes the map does not re-draw to display the additional detail.
This feels a lot like the previous BC version bug in which blank tiles would remain during a re-draw, only instead of blank it simply fails to draw the new items (smaller roads, POIs) that should appear as you zoom in.
I think there have been several minor OS updates since we all wrestled with that pervious bug. I am now running OS 10.7.4 on an i3 iMac.
-dan