I see there is a bug when employing multiple processor rendering to process layer maps.
(System here: Mac AECS3, quad core)
My layer map looks perfect when I scrub the timeline but when I preview or render a movie--the texture drops off and is replaced with that grey "texture map" placeholder. I am then forced to manually go in and reselect the layer map.
My current work-around: If I turn off multiple rendering then everything works fine.
Are you using Nucleo and Invigorator Pro/Classic? Are you actually dropping your textures in the timeline and setting them to layer maps, or assigning them in the Set Up window by pointing to the file on your hard drive? I posted the same problem here a few days ago:
I haven't heard anything on a fix, but did find a workaround. I posted it in the link above.
Basically, if you go into the set up window and assign a layer map by actually pointing at the file it drops it when you render with multiprocessors. If you actually drop it in your timeline and assign it to a Layer Map through Invigorator, it works. Or it has for us. Really limits what you can map, though, since there are only 8 or 9 layer maps.