Non-const BlueprintNativeEvent in AnimNotifyState subclass

Development Programming & Scripting Blueprint
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1

This code does not work:

// h file
#pragma once

#include "Animation/AnimNotifies/AnimNotifyState.h"
#include "Components/SceneComponent.h"
#include "ComponentAdder.generated.h"

//UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
//class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public USceneComponent
UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public UAnimNotifyState
{
  GENERATED_BODY()

public:
  UFUNCTION(BlueprintNativeEvent)
    FString A();
};

// cpp file
#include "StarterContent_4_13.h"
#include "ComponentAdder.h"

FString UAnimNotifyState_ComponentAdder::A_Implementation()
{
  return FString("");
}

This code works:

// h file
#pragma once

#include "Animation/AnimNotifies/AnimNotifyState.h"
#include "Components/SceneComponent.h"
#include "ComponentAdder.generated.h"

UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public USceneComponent
//UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
//class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public UAnimNotifyState
{
  GENERATED_BODY()

public:
  UFUNCTION(BlueprintNativeEvent)
    FString A();
};
// cpp file
#include "StarterContent_4_13.h"
#include "ComponentAdder.h"

FString UAnimNotifyState_ComponentAdder::A_Implementation()
{
  return FString("");
}

The errors that are thrown come from the header tool not being able to understand that the function is non-const:

Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Source\StarterContent_4_13\ComponentAdder.cpp(7) : error C2511: 'FString UAnimNotifyState_ComponentAdder::A_Implementation(void)': overloaded member function not found in 'UAnimNotifyState_ComponentAdder'
Error c:\users\silentsniperoo\desktop\ideapad\projects\startercontent_4_13\source\startercontent_4_13\ComponentAdder.h(12) : note: see declaration of 'UAnimNotifyState_ComponentAdder'
Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Intermediate\Build\Win64\UE4Editor\Inc\StarterContent_4_13\StarterContent_4_13.generated.cpp(14) : error C2511: 'FString UAnimNotifyState_ComponentAdder::A(void) const': overloaded member function not found in 'UAnimNotifyState_ComponentAdder'
Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Source\StarterContent_4_13\ComponentAdder.h(12) : note: see declaration of 'UAnimNotifyState_ComponentAdder'
Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Intermediate\Build\Win64\UE4Editor\Inc\StarterContent_4_13\StarterContent_4_13.generated.cpp(16) : error C2671: 'UAnimNotifyState_ComponentAdder::A': static member functions do not have 'this' pointers
Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Intermediate\Build\Win64\UE4Editor\Inc\StarterContent_4_13\StarterContent_4_13.generated.cpp(16) : error C2227: left of '->ProcessEvent' must point to class/struct/union/generic type
Error C:\Users\SilentSniperoo\Desktop\ideapad\Projects\StarterContent_4_13\Intermediate\Build\Win64\UE4Editor\Inc\StarterContent_4_13\StarterContent_4_13.generated.cpp(16) : error C2352: 'UObject::FindFunctionChecked': illegal call of non-static member function
Error c:\program files\epic games\ue_4.13\engine\source\runtime\coreuobject\public\uobject\UObject.h(745) : note: see declaration of 'UObject::FindFunctionChecked'

Thus, this code works as well:

// h file
#pragma once

#include "Animation/AnimNotifies/AnimNotifyState.h"
#include "Components/SceneComponent.h"
#include "ComponentAdder.generated.h"

//UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
//class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public USceneComponent
UCLASS(Blueprintable, meta = (DisplayName = "Create Things"))
class STARTERCONTENT_4_13_API UAnimNotifyState_ComponentAdder : public UAnimNotifyState
{
  GENERATED_BODY()

public:
  UFUNCTION(BlueprintNativeEvent)
    FString A() const;
};

// cpp file
#include "StarterContent_4_13.h"
#include "ComponentAdder.h"

FString UAnimNotifyState_ComponentAdder::A_Implementation() const
{
  return FString("");
}

Obviously, this is a problem since this means AnimNotifyState subclasses cannot have blueprint overridable events with default C++ implementations AND non-const side effects.