diff --git a/Source/Unrealzilla/Private/BugMarkerSubsystem.cpp b/Source/Unrealzilla/Private/BugMarkerSubsystem.cpp
index 22ef8da..9f07074 100644
--- a/Source/Unrealzilla/Private/BugMarkerSubsystem.cpp
+++ b/Source/Unrealzilla/Private/BugMarkerSubsystem.cpp
@@ -140,19 +140,19 @@ void UBugMarkerSubsystem::LoadNewBatch()
 
 void UBugMarkerSubsystem::FormPrepResponseCallback(const FUnrealzillaFormPrepData &Data)
 {
-	this->FormPrepResponse.Execute(Data);
+	this->FormPrepResponse.ExecuteIfBound(Data);
 }
 
 void UBugMarkerSubsystem::POSTResponseCallback(const TArray<FUnrealzillaBugData> &Data)
 {
 	if (!Data.IsEmpty())
 	{
-		this->FormPostResponse.Execute(Data[0]);
+		this->FormPostResponse.ExecuteIfBound(Data[0]);
 	}
 }
 
 
 void UBugMarkerSubsystem::ErrorResponseCallback(const FUnrealzillaErrorData &Error)
 {
-	this->ErrorResponse.Execute(Error);
+	this->ErrorResponse.ExecuteIfBound(Error);
 }