Well, I've gotten kinda tired of living with this, and I haven't found any information regarding it, so I've decided to go ahead and post this.
Sometimes, for no apparent reason, many of the textures, thumbnails, menu text, and other images in the game will end up scrambled-looking, resembling nothing like what they're supposed to be. Just look at the following picture, really:
Basically, you can't tell what anything is. It affects ship thumbnails, planet textures, race logos, menu graphics...
There's no rhyme or reason to when it happens; I've had it show up before I've even gotten through a single turn, and I've played for hours straight without ever seeing it. No specific menu or other action seems to trigger it, either.
My computer is a 2.1GHz AMD Athlon XP 2800+ with 1.5GB RAM, and my graphics card is a 256MB ATI Radeon 9600 with Catalyst 6.6.
Thanks in advance.