Well, I wasn't able to reproduce the issue, (alternated between the jump maps payl suggested as well as trying several other maps that have .wal files), but I think I've tracked down what the issue is. It is likely heavily driver dependent, which explains why some people see it more often than others. What video card do you have, payl and BASEBALLDUDE?
The issue is this:
Quake2 never handled texture ID generation properly. The way you're SUPPOSED to do things is call glGenTextures to get a list of texture ID's that can be used. Quake2 simply uses its own hard-coded texture ID's. There are, however, a few instances with newer features where glGenTextures is used, and is likely generating conflicting texture ID's. I'm going to try to make the old code use glGenTextures properly and maybe this problem will go away.