BlueprintImplementableEvent Crash on UE5

Hi,
I am trying to call a function from blueprint every time I receive an http message with a BlueprintImplementableEvent.
When I play start the application works correctly, but if I stop the application and I press another time play, the application crash.

UFUNCTION(BlueprintImplementableEvent, BlueprintCallable)
void OnVideocallMessage(EVideocall Videocall);
bool AXChangeServerGameMode::ParseVideocallMessage(FString Message)
{
	FXChangeState RequestData;
	bool Success = GetStateFromRequestBody(Message, "Videocall", RequestData);
	if (Success == false)
	{
		return false;
	}
	XChangeState.Videocall = RequestData.Videocall;

	OnVideocallMessage(XChangeState.Videocall);

	return true;
}

I resolve like that.

bool AXChangeServerGameMode::ParseVideocallMessage(FString Message)
→ bool AXChangeServerGameMode::ParseVideocallMessage(const FString& Message)