Editor crash on Garbage Collection within UEdGraphPin::BreakLinkTo

Atm the editor is consistently crashing for me on

void UEdGraphPin::BreakLinkTo(UEdGraphPin* ToPin)
...
			ensureAlwaysMsgf(ToPin->LinkedTo.Contains(this), *GetLinkInfoString(LOCTEXT("BreakLinkTo", "BreakLinkTo").ToString(), LOCTEXT("NotLinked", "not reciprocally linked with pin").ToString(), ToPin));

whenever I have one of our behaviour trees open or have opened at some point and try to run the game or save I get a crash on this line, its making it very difficult to debug our AI. The callstack looks like

UE4Editor-Engine.dll!UEdGraphPin::BreakLinkTo(UEdGraphPin * ToPin) Line 292	C++
UE4Editor-Engine.dll!UEdGraphPin::BreakAllPinLinks() Line 308	C++
UE4Editor-Engine.dll!UEdGraphPin::DestroyImpl(bool bClearLinks) Line 1199	C++
UE4Editor-Engine.dll!UEdGraphNode::BeginDestroy() Line 424	C++
UE4Editor-CoreUObject.dll!UObject::ConditionalBeginDestroy() Line 739	C++
UE4Editor-CoreUObject.dll!CollectGarbageInternal(EObjectFlags KeepFlags, bool bPerformFullPurge) Line 1281	C++
UE4Editor-CoreUObject.dll!CollectGarbage(EObjectFlags KeepFlags, bool bPerformFullPurge) Line 1320	C++
UE4Editor-Engine.dll!UGameInstance::InitializePIE(bool bAnyBlueprintErrors, int PIEInstance, bool bRunAsDedicated) Line 183	C++
UE4Editor-UnrealEd.dll!UEditorEngine::CreatePIEGameInstance(int InPIEInstance, bool bInSimulateInEditor, bool bAnyBlueprintErrors, bool bStartInSpectatorMode, bool bRunAsDedicated, float PIEStartTime) Line 2946	C++
UE4Editor-UnrealEd.dll!UEditorEngine::PlayInEditor(UWorld * InWorld, bool bInSimulateInEditor) Line 2426	C++
UE4Editor-UnrealEd.dll!UEditorEngine::StartQueuedPlayMapRequest() Line 1141	C++

And the behaviour tree looks like

I have been through all the behaviour trees trying to find out where a loose node might be but cannot find anything, I am thinking that my next approach will involve recreating the assets from scratch hoping that its just some legacy serialization thats causing the issue?

Ok nevermind its not a crash its just hitting a assertion multiple times, I’ve compiled it out as I was having to skip through about 20 whenever I reopened the editor( thought it was crashed but the garbage collector was just cleaning up multiple instances with the same callstack), not too worried anymore, will chase it up when not trying to make a build for PAX.