Just to let you know... I myself have this awesome game, but when I run it, it doesn't seem to do this. What it might be is that i have 2 Gigs of RAM... the game it's self uses like 800-900 megs on full settings. I only had system processes and battlefield 2 memmory and my system was using 1.1 gigs of ram... so that might be it...
The game might be trying to automatically lower your settings because it knows it's running out of RAM