Group:Number:SUM not updated by subgroup with Switch created by adding Thing via Paper UI

You know that when you have a Group defined in a .items file with the “home-group” tag,
that group becomes available in the Paper UI when you want to add new Things and assign it to that group.

The problem I have encountered with this is the following:
I have a group called Sensors defined as

Group:Number:SUM Sensors "Sensors" [home-group]

Which I intend to add sensors to, obviously. I have added a fake sensor like this

Group:Switch:AND(ON, OFF) FakeSensor "Fake Sensor" (Sensors) Switch FakeSensorSwitch "Fake Sensor Switch" (FakeSensor)

And this works as expected, if I turn the FakeSensorSwitch on via the Paper UI or via a REST call, the Sensors group also updates.

Now when I add a real Thing (call it RealSensor) from a binding with a channel-type Switch to this group via the Paper UI (Setup Wizard > + > Select Binding > Add Manually >…) , with advanced mode off btw, openhab will create a Group item with a Switch member for this thing (like the fake one I made) and link it to that thing.

However if there is an update of the sensor, the Switch item will update, its Group item as well, however the Sensors group does not get updated for some reason…

Might it be that the group item of the real sensor does not have a base type (e.g. Switch) and/or function associated with it? is there any way to check this?

Any idea how to address this? Is this a bug perhaps? Is the functionality simply not available?