I also experience this bug. On first mission all is OK, on second its a random combination of artifacted background textures, unreadable fonts (shown somewhere on forum, vertical lines instead of letters) and broken model geometry. This only happens in CVS builds after 17th may, but doesn't occur under Linux (my own builds, latest CVS). It also seems that environment map is rendered with artifacted backgrounds when flying first mission, I once saw those errors in reflected nebula.
Radeon 9800 pro, catalyst 6.4, 6.5.