Q_OBJECT_COMPAT_PROPERTY binding removal inconsistent

#include <QObject>
#include <QDebug>

#include <private/qproperty_p.h>

class Foo : public QObject {
    Q_OBJECT
    Q_PROPERTY(int a READ a WRITE setA NOTIFY aChanged BINDABLE bindableA)

public:
    int a() const { return Adata; }
    void setA(int value) {
        int oldvalue = Adata;
        Adata = value;
        if (value != oldvalue)
            emit aChanged(value);
    }
    QBindable<int> bindableA() { return &Adata; }

    signals:
    void aChanged(int);

private:
    Q_OBJECT_COMPAT_PROPERTY(Foo, int, Adata, &Foo::setA)
};

int main(){
    QProperty<int> refvalue(5);

    Foo myfoo;
    myfoo.bindableA().setBinding([&](){ return refvalue.value(); });

    // once myfoo.a becomes 10 or greater, we want it to stop updating
    QObject::connect(&myfoo, &Foo::aChanged, [&](int value){
        if (value >= 10){
            myfoo.setA(value);
        }
    });

    // change refvalue, myfoo.a follows
    refvalue = 6;
    assert(myfoo.a() == 6);

    refvalue = 8;
    assert(myfoo.a() == 8);

    refvalue = 10;
    assert(myfoo.a() == 10);

    refvalue = 12;
    assert(myfoo.a() == 10);
}

#include "main.moc"