Auto-Importing FBX causes crash

I’m trying to create an auto-importer for FBX files. I have gotten the process to work with default settings - I run a custom console command to import the files when the editor is loading.
When I try to close the editor, though, Unreal crashes with the following report:

MachineId:4EF88B5A43B14A50FF02CFADD93CC151
EpicAccountId:ad69e71135ea4e3c95d9d3145fe028b0

Access violation - code c0000005 (first/second chance not available)

UE4Editor_Core!rml::internal::Block::freePublicObject()

UE4Editor_Core!rml::internal::ExtMemoryPool::initTLS()

UE4Editor_Core!FMallocTBB::Free() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\hal\malloctbb.cpp:115]

UE4Editor_Core!FMemory::Free() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\hal\fmemory.inl:49]

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

libfbxsdk

UE4Editor_UnrealEd!UnFbx::FFbxImporter::CleanUp() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\fbx\fbxmainimport.cpp:339]

UE4Editor_UnrealEd!SharedPointerInternals::TReferenceControllerWithDeleter >::DestroyObject() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\templates\sharedpointerinternals.h:104]

UE4Editor_UnrealEd!UnloadFBxLibraries() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\fbx\fbxlibs.cpp:44]

UE4Editor_UnrealEd!FUnrealEdMisc::OnExit() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\unrealedmisc.cpp:814]

UE4Editor_UnrealEd!EditorExit() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\unrealed.cpp:186]

UE4Editor!GuardedMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launch.cpp:156]

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

It seems like there’s some sort of issue with how memory is being cleaned up when the editor closes. Is there some function I should be calling after ImportAssets? Or some sort of pointer I should be deleting manually?

Any help is much appreciated.