Creating and loading 1001+ instances of level crashes editor

Creating and loading 1001+ instances of level crashes editor.

Frequency: 4/4

Crashreporter: [Link Removed]

Regression (yes) issue (does not) occur in 4.11.2

Notes While not reproduced internally with a new project, it consistently reproduces in provided project. User reports that the error occurs in a clean, blank project with no additional content.

1. Download, unzip, open attached project
2. Open map_main
3. Press PIE
4. Wait until 1001 instances are loaded

Results

Editor crashes

Expected

1001 instances are created and more are created after.

MachineId:409D523543AE785961A2788C698A2F90
EpicAccountId:89e014249c0a480eb18ea5b683d2eb3c

Fatal error: [Link Removed] [Line: 2181]
LoadPackageAsync failed to begin to load a package because the supplied package name was neither a valid long package name nor a filename of a map within a content folder: ''

UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:440]
UE4Editor_CoreUObject!LoadPackageAsync() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:2181]
UE4Editor_Engine!ULevelStreaming::RequestLevel() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\levelstreaming.cpp:484]
UE4Editor_Engine!UWorld::UpdateLevelStreamingInner() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\world.cpp:2475]
UE4Editor_Engine!UWorld::UpdateLevelStreaming() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\world.cpp:2549]
UE4Editor_Engine!UGameViewportClient::Draw() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\gameviewportclient.cpp:1050]
UE4Editor_Engine!FViewport::Draw() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\unrealclient.cpp:1149]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1531]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:368]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2775]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launch.cpp:148]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build\++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll