When I add a slot with return value to rep file and pass a replica to qml, then if called the slot in qml, the qml engine complains about:

Error: Unknown method return type: QRemoteObjectPendingCall

After registering this kind of type in somewhere like main function, this problem is solved. Registering code is:

qRegisterMetaType<QRemoteObjectPendingCall>();

However, I think this should be done by the QtRO module itself, not manually by me.

Demo that reproduces this issue is attached.