signal of dynamic-property imported by QQmlPropertyMap will always be emitted by qml component whenever property has changed

The problem was found since i import qml with dynamic-property, maybe in version 5.2 or 5.3, but still exists in the latest version 5.5.
Following is my c++ code:
QQmlPropertyMap* map = new QQmlPropertyMap;
map->insert("abc", false);

QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty("myObject", map);
...
and then, the qml code:
Connections {
target: myObject
onAbcChanged:

{console.log("abc changed! ", myObject.abc)}

}

mouseArea.onClicked:

{ myObject.abc = true; console.log("mouse clicked!") }

last, the result in console:
qml: abc changed! true
qml: mouse clicked!
qml: abc changed! true
qml: mouse clicked!
qml: abc changed! true
qml: mouse clicked!
......

For this problem, i read the Qt's source code, and catched a probable reason. i corrected the error logic in souce code ,and recompiled it, achived a fixed version of QtQmld.dll. With the fixed version, my problem had been resolved.

Following is the source code:
file-> src/qtdeclarative/src/qml/qml/qqmlopenmetaobject.cpp
function-> metaCall, line->242
241 else if (c == QMetaObject::WriteProperty) {
242 if (propId <= d->data.count() || d->data[propId].first != *reinterpret_cast<QVariant *>(a[0]))

{ 243 propertyWrite(propId); ... ... 249 }

In line 242, the propId of existed property will always be lower than d->data.count(), so the property will always be written and signal will be emitted.

I modified "<=" to be ">=", and then, for existed property, value comparison will be done, and signal will not be emitted by qml-same-value. for new-added property, its propId will be larger than or equals with data.count(), value will be written and signal will be emitted.