Doesn't have anything to do with the scenery, and I can see this on FS9 at each and every airport, even default ones with nothing installed, and happens in full screen only, and only with Window 7.
You are having the wrong impression it happens at KLAX only, because the scenery takes more time to load, so you have enough time to notice the cursor being a black circle, but it happens everywhere, just it last much less, so you don't really notice it.