Blueprint class's property is overridden by parent blueprint class

if ( bShouldInstance ) 
{ 
     // check bIsRuntime first
     bool bIsRuntimeInstance = CurrentValue != SourceSubobject && CurrentValue->GetOuter() == CurrentObject; 
     if (bDoNotCreateNewInstance || bIsRuntimeInstance) 
     { 
           InstancedSubobject = CurrentValue; 
     } 
     else {
         // do anything else 
         ...
     }
}

UCLASS(EditInlineNew, DefaultToInstanced, Abstract, BlueprintType, Blueprintable)
class INSTANCETESTPROJECT_API USubObject : public UObject
{
      GENERATED_BODY()
public: 
      UPROPERTY(EditAnywhere) 
      FString String;
};

UCLASS(BlueprintType, Blueprintable, meta = (BlueprintSpawnableComponent))
class INSTANCETESTPROJECT_API UExampleComponent : public UActorComponent
{
      GENERATED_BODY()
public:
      UPROPERTY(EditAnywhere, Instanced)               
      class USubObject* SubObject = nullptr;
};

UCLASS(BlueprintType, Blueprintable)
class INSTANCETESTPROJECT_API ATestBPChildGameModeBase : public AGameModeBase
{
      GENERATED_BODY()  
      ATestBPChildGameModeBase()
      { 
            ExampleComp = CreateDefaultSubobject<UExampleComponent>(TEXT("ExampleComp")); 
      }
public: 
      UPROPERTY(EditAnywhere) 
      class UExampleComponent* ExampleComp;
};