Having lots of SpeedTrees loaded in/out/in with level streaming causes crash with Standalone game

Description: When using lots of static meshes placed in the scene and using level streaming to switch levels out can cause standalone game to crash while loading the map back in. For example, if you load Map 1 with loads of SM's and unload and load in Map 2 then Unload and Load back in Map 1 the crash will occur.

Call Stack:
MachineId:621DFBAB44A9B51A4245D5A61065407D
UserName:TimHobson

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: !HasAnyFlags(RF_NeedLoad|RF_NeedPostLoad) [File[Image Removed]:\BuildFarm\buildmachine_++depot+UE4\Engine\Source\Runtime\CoreUObject\Private\UObje

KERNELBASE + 23544 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() + 248 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() + 1042 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\core\private\misc\outputdevice.cpp:224]
UE4Editor_CoreUObject!UObject::SetLinker() + 436 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\coreuobject\private\uobject\uobjectlinker.cpp:96]
UE4Editor_CoreUObject!UObject::BeginDestroy() + 71 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\coreuobject\private\uobject\obj.cpp:456]
UE4Editor_CoreUObject!UObject::ConditionalBeginDestroy() + 388 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\coreuobject\private\uobject\obj.cpp:567]
UE4Editor_CoreUObject!CollectGarbage() + 1757 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\coreuobject\private\uobject\garbagecollection.cpp:1153]
UE4Editor_Engine!UWorld::Tick() + 8716 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\engine\private\leveltick.cpp:1285]
UE4Editor_Engine!UGameEngine::Tick() + 1358 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\engine\private\gameengine.cpp:830]
UE4Editor!FEngineLoop::Tick() + 4084 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\launch\private\launchengineloop.cpp:2263]
UE4Editor!GuardedMain() + 1344 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

Attached files:

[Link Removed]
Project that will crash - Launch in Standalone mode to see the level switch and crash associated. If in editor it will not crash. Check Level BP for streaming and key presses if that method is preferred.

Broadleaf Desktop SpeedTree Example: [Link Removed]

These steps are kinda iffy as it can take a lot:

1. Open UE4
2. Import the BroadLeaf SpeedTree example (attached)
3. Set up a Pesistent, Map 1 and Map 2
4. Place lots meshes in Map 1, NOT using the foliage tool
5. Play in Standalone Game

Expected: The meshes streaming back in when Map 1 reloads back in via level streaming will not cause a crash when playing in standalone game.

Results: Using a lot of speedtree meshes in map 1 that gets streamed out and then streamed back in after map 2 is unloaded causes a crash in Standalone game only. In the editor everything functions correctly.