QProperty onChangeValued() calls the callback to many times

#include <QProperty>

int main(int argc, char *argv[])
{
    QProperty<int> x;
    QProperty<int> y;
    QProperty<int> z(10);
    QProperty<QString> str;

    int xCount = 0;
    x.setBinding([&]() {
        xCount++;
        return y.value() * 10;
    });

    int yCount = 0;
    y.setBinding([&]() {
        yCount++;
        return z.value() * 5;
    });

    int strCount = 0;
    str.setBinding([&](){
        strCount++;
        return QString("x:%1 y:%2 z:%3").arg(x.value()).arg(y.value()).arg(z.value());
    });

    int valueChangeCount = 0;
    auto valueChangedHandle = str.onValueChanged([&valueChangeCount, &str](){
        valueChangeCount++;
        qDebug() << "Called:" << str.value();
    });

    z.setValue(13);

    //Change valueChangeCount should only be 1, instead of 3?
    qDebug() << "Str:" << valueChangeCount << str.value() << valueChangeCount;
}