Json serialization for QVariantMap is a mismatch between qt5 and qt6

QVariantMap map = QVariantMap({ { QStringLiteral("data"), QDateTime() } });
qDebug().noquote() << QJsonDocument::fromVariant(map).toJson(QJsonDocument::Compact);

QJsonObject jo;
jo[QStringLiteral("data")] = QJsonValue::fromVariant(QVariant(QDateTime()));
qDebug().noquote() << QJsonDocument(jo).toJson(QJsonDocument::Compact);  

A different output when running the code above in Qt5 and Qt6

Output of Qt5 (5.6.0):

{"data":null}
{"data":null} 

Output of Qt6 (6.3.1), expected output is the same as Qt5 but it not:

{"data":""}
{"data":null}

I am having trouble upgrading from Qt5 to Qt6 because this change is breaking my handle.

I have a workaround that checks whenever QDateTime is null(), then inserts QVariant().

QVariantMap map;
map.insert(key, date.isNull() ? QVariant() : date);

Is there any other solution for this?

*I have searched but couldn't find any documents or bugs related to this, so I created this ticket. I hope you guys will respond soon. Many thanks.