QLocale not correctly restored from QSettings

// Make an English locale
QLocale locale(QLocale::English);
// Set a number option flag, that differs from English locale
locale.setNumberOptions(QLocale::OmitGroupSeparator);
QVariant variant = locale;
// This returns true, as expected.
QVERIFY(variant.toLocale().numberOptions().testFlag(QLocale::OmitGroupSeparator));

QSettings settings;
settings.setValue("key", variant);
QLocale locale2 = settings.value("key").toLocale();
// This will fail 
QVERIFY(locale2.numberOptions().testFlag(QLocale::OmitGroupSeparator));