It could also be a graphics driver issue related to the legacy OpenGL code interacting with the fgviewer/osgviewer main loop - to see if it's related to being out of out-of-ram, you could try to load the same cockpit using fgviewer standalone, try any combination of
draw-masks (prior to starting, see the wiki for details) and then report back here to troubleshoot this step by step.
If you are into tinkering (as in Nasal coding), there also is a snippet of Nasal code that could be extended to load instruments/cockpit panels using native OSG code via the Canvas subsystem:
http://wiki.flightgear.org/Howto:Parsin ... the_CanvasIt may not look that well, and won't be functional (hot spots / bindings) in its current form, but should be able to load most of the same textures without too much effort, so should put pretty much the same load on the GPU - without going through the legacy 2D panels code:
http://wiki.flightgear.org/Unifying_the ... via_canvas Obviously, you can safely ignore all of this if the bug disappears when disabling effects/shaders