At runtime, I duplicate a material, and register the new matierl with the entities graphics system (EntitiesGraphicsSystem.RegisterMaterial). I get back the material ID which I assign to the MaterialMeshInfo. This all works correctly. But when I maximise game view (double click on game tab), all the materials break and I'm left with the pink shader error.
This does not happen when I use materials that are not registered with the EntitiesGrpahicsSystem at runtime.