Failed to route PostInitProperties

When I experiment with this crash another error shows up sometimes:

Error: === Critical error: ===
Error:
Error: Assertion failed: !bCheckAdded || NodeRef.bAddedToGraph [File:D:/Build/++UE4+Licensee/Sync/Engine/Source/Runtime/CoreUObject/Private\Serialization/AsyncLoading.h] [Line: 249]
Error:
Error: [Callstack] 0x00000000CA58BAD4 libUE4.so(0x000000000656BAD4)!FEventLoadGraph::RemoveNode(FEventLoadNodePtr&)  []
Error: [Callstack] 0x00000000CA5A3A48 libUE4.so(0x0000000006583A48)!FAsyncPackage::MakeNextPrecacheRequestCurrent()  []
Error: [Callstack] 0x00000000CA59B0B8 libUE4.so(0x000000000657B0B8)!FAsyncPackage::ProcessImportsAndExports_Event()  []
Error: [Callstack] 0x00000000CA59A788 libUE4.so(0x000000000657A788)!FAsyncPackage::Event_ProcessImportsAndExports()  []
Error: [Callstack] 0x00000000CA5A7F5C libUE4.so(0x0000000006587F5C)!FAsyncLoadingThread::ProcessAsyncLoading(int&, bool, bool, float, FFlushTree*)  []
Error: [Callstack] 0x00000000CA5B1710 libUE4.so(0x0000000006591710)!FAsyncLoadingThread::TickAsyncThread(bool, bool, float, bool&, FFlushTree*)  []
Error: [Callstack] 0x00000000CA5B34E4 libUE4.so(0x00000000065934E4)!FAsyncLoadingThread::Run()  []
Error: [Callstack] 0x00000000CA0D3B70 libUE4.so(0x00000000060B3B70)!FRunnableThreadPThread::Run()  []
Error: [Callstack] 0x00000000C9FD9A38 libUE4.so(0x0000000005FB9A38)!FRunnableThreadPThread::_ThreadProc(void*)  []
Error: [Callstack] 0x00000000F2B27DA2 libc.so(0x0000000000071DA2)![Unknown]()  []
Error: [Callstack] 0x00000000F2AD3E32 libc.so(0x000000000001DE32)![Unknown]()  []