Fatal Crash from async loading and phys materials

Exception thrown: read access violation.

this was nullptr.

I’ve spent days now trying to find the source of the problem, but I’ve not been able to narrow it down yet. Here are some more error details from debugging in visual studio:

--- h:\unrealengine-release\engine\source\runtime\engine\private\physicsengine\physicalmaterial.cpp 


#if WITH_PHYSX
PxMaterial* UPhysicalMaterial::GetPhysXMaterial()
{
00000001410CCD20  push        rbx  
00000001410CCD22  sub         rsp,20h  
	if((PMaterial == NULL) && GPhysXSDK)
00000001410CCD26  cmp         qword ptr [rcx+68h],0  (<------BREAK POINT)



>	Game-Win64-Shipping.exe!UPhysicalMaterial::GetPhysXMaterial() Line 114	C++

Still working on reproducing this issue…