Graph is linked to external private object when using custom class

I created a custom C++ class actor and using a class reference for it in my Player BP. Everything is fine until I create the variable to hold the class. Then when i want to save it it says

Can’t save
…/…/…/…/…/…/Users/Thorwin/Documents/Unreal
Projects/Project/Content/Blueprints/PlayerShipPawn.uasset:
Graph is linked to private object(s)
in an external package. External
Object(s): /Engine/Transient Try to
find the chain of references to that
object (may take some time)?

The code for my custom class header file:

#pragma once

#include "GameFramework/Actor.h"
#include "SmallShipClass.generated.h"

UCLASS()
class PROJECT_API ASmallShipClass : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	ASmallShipClass();

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	
	// Called every frame
	virtual void Tick( float DeltaSeconds ) override;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Ship Data")
	FString Name;
	
};

Isnt Name already declared for all Objects?

Ok i found out, that it isnt that class which causes the problem. It is a non-public BPFuctionslibrary