Graph is linked to private object(s) in an external package.

I encountered my favorit error again.

I thought I did fix my setup now using a UStruct instead a UClass, but this dont seem to fix my problem.
I have no really no idea what is causing this error.

I try to make a n-dimensional vector, which works like the FVector, so I looked into Vector.h and KismetMathLibrary and KismetStringLibrary and build the following setup:

NVector.h:

#pragma once

#include "NVector.generated.h"

USTRUCT(BlueprintType)
struct FNVector
{
   GENERATED_BODY()

   /* nVector's components. */
   UPROPERTY(BlueprintReadWrite)
   TArray<float> Coordinates;

   /* Default constructor (no initialization). */
   FORCEINLINE FNVector();

   /* constructor to set n-Dimensions */
   FORCEINLINE FNVector(const TArray<float> InCoordinates);

   FString ToString() const;
};

FORCEINLINE FNVector::FNVector()
{}

FORCEINLINE FNVector::FNVector(const TArray<float> InCoordinates)
   : Coordinates(InCoordinates)
{}

FORCEINLINE FString FNVector::ToString() const
{
   FString s = "";
   s += "{";

   for(int i = 0, max = Coordinates.Num(); i < max; i++)
   {
      s += FString::SanitizeFloat(Coordinates[i]);
      if(i < (max - 1))
      {
         s += ", ";
      }
   }
   s += "}";

   return s;
}

MathLabLibrary.h:

#pragma once

#include "Kismet/BlueprintFunctionLibrary.h"
#include "Math/NVector.h"
#include "MathLabLibrary.generated.h"

UCLASS()
class MATHLAB_API UMathLabLibrary : public UBlueprintFunctionLibrary
{
   GENERATED_BODY()

public:
   /* Converts a n-vector value to a string, in the form '{x, y, z, ...}' */
   UFUNCTION(BlueprintPure, DisplayName = "ToString (nVector)", Category = "Math Lab|Utilities|String", meta = (CompactNodeTitle = "->", BlueprintAutocast))
   static FString Conv_NVectorToString(FNVector InVec);
};

MathLabLibrary.cpp:

#include "MathLab.h"
#include "MathLabLibrary.h"

FString UMathLabLibrary::Conv_NVectorToString(FNVector InVec)
{
   return InVec.ToString();
}

When I go now into a Blueprint, in my case CoordinateSystem, and want to use my structure like this:

123653-unbenannt2.jpg

(Compile Blueprint, everything works)

When I than change something in my Code and try to Compile the Blueprint, I get following Error:

123654-unbenannt.jpg

I have no idea what is causing the error Message. I tried to understand the logic how the FVector is created and works and copy that for my NVector.

I searched in the Bug reports and found this Bug UE-36428.

It seems like this is my Problem, am I right?