memory leak while calling a c++ object methode with boolean return type in javascript

Executing a simple QML-Script with the QmlEngine like this:

import QtQml 2.2
import "file:///E:/Dev/Qt-Test/JavaScriptMemoryLeak/Testskript/MemoryLeak.js" as SPS_Script
QtObject

{ id: root; property var scriptReturn: SPS_Script.main() }

where the java script function "main()" ist defined as:

function main()
{
var counter = 0;
var isExit = false;
while(!isExit)

{ isExit = exitController.oIsExitRequest(); // no memory leak if this line is removed counter++; }

return "done: counter = " + counter;
}

cause a memory leak while calling a c++ object methode "bool oIsExitRequest() const".
The c++ object is handed over with
"mEnginePtr->rootContext()->setContextProperty("exitController", &mExitController);".
The memory leak increases with each call of "oIsExitRequest()".
Manually triggering the garbage collector has no effect.
The attached VS2015 Project shows the memory leak in action.