Please take a look at this video i made (takes one minute). Its realy weird and i dont find answers in the internet.
after switching my mesh to a new skin ingame i got serveral material bugs (The mesh and the materials are working and not broken! After restarting the app the broken mesh is showed as wished.) To switch my skin i just change the skeletal mesh from my character. After that I’m reloading my map, thats it.