I had a custom SceneComponent that would break when a Blueprint inherited from a Blueprint that had my component. I was able to fix it by following that thread.
I wanted to attach a couple StaticMeshComponent to my custom SceneComponent.
Constructor:
StaticMeshComponent1->SetupAttachment(this);
StaticMeshComponent0->SetupAttachment(this);
OnRegister:
Super::OnRegister();
this->StaticMesh1->AttachToComponent(this, FAttachmentRules::KeepRelativeTransform);
this->StaticMesh0->AttachToComponent(this, FAttachmentRules::KeepRelativeTransorm);