If I know right the A&M mods uses custom shaders with the sponsors as a second layer of the base 3D.
Maybe AMS don't work it those shaders, and when this happens, the game just don't load it. (and you have only the base 3D).
"how to fix?" - Well... only editing all 3Ds of the mod to change the shaders to one that AMS actually reads or found a way to make AMS read this custom shader.