Why does my destructible not show textures inside while in Physx lab it does

When I create a destructible mesh it does not show inside textures and i couldnt find a solution to this problem. I tried to use physx lab to fracture the model and as a result there was inside texture:

I then exported the file from physx lab and imported it into UE4 but then when I tried again the inside was hollow again. Since both unreal and Physx lab are basically the same technical idea since unreal HAS it inside the engine already why isnt this working.