I ran into this in UE 4.20.
It looks like the bug is that, when scanning for references after hot reloading, it’s dereferencing “ClusterTreePtr” - which is null for the class default object.
My workaround for now is to override “Serialize()” like so:
void UMyDerivedHISMComponent::Serialize(FArchive& Ar)
{
bool hasTempClusterTreePtr = false;
if (Ar.IsObjectReferenceCollector() && !ClusterTreePtr.IsValid())
{
ClusterTreePtr = MakeShareable(new TArray<FClusterNode>);
hasTempClusterTreePtr = true;
}
Super::Serialize(Ar);
if (hasTempClusterTreePtr)
{
ClusterTreePtr = nullptr;
}
}