Revisioned properties not available in subclasses present in different QML plugins

Subclassing SomeClass from QtQuick in a separate QML plugin and registering it as CustomModule 2.10 disables all signals, properties and invokables revisioned.
E.g., "MyImage.mipmap" is not available in MyModule 2.10.

with
class MyImage : public QQuickImage

In this test i explicitly tried to register CustomModule as 2.10, hoping that the revision was done solely on the revision number.