Cannot have a property that returns a QQmlPropertyMap object - works in PyQt6 though

Create a python QObject derived class with a @Property of type QQmlPropertyMap.

Register the python class using qmlRegisterType

In QML, create one of those objects and attempt to reference the property.  Fails with errors:

QMetaProperty::read: Unable to handle unregistered datatype 'QQmlPropertyMap*' for property 'Car::testmap'
file:///qtbug5/main.qml:22: TypeError: Cannot read property 'testkey' of undefined

Simplified minimal repro files attached.

Same files work fine with PyQt6