The satellites will connect wirelessly for backhaul to the router node and all looks well, but

That's been my experience as well.    The satellites will connect wirelessly for backhaul to the router node and all looks well, but if you use wired backhaul connections (via a switch network), it actually tries to use both.  On my switches, that generated LOOP alarms and I had to unplug the wired backhaul.  The way to get around that was to plug in the wired backhaul first before turning on the satellites, then the wireless backhaul doesn't get turned up, with the additional downside that the APP (and the web admin page) say there are NO satellites.  You can however log into each of the satellites and see that they ARE connected (via the wired backhaul) and devices are connecting and working fine.

Besides the bogus info in the app, the app is UNABLE to see connections on the satellites and therefore cannot give you a unified view of all your connected devices (it can only show you what is connected to the router node).

A game you can play to trick the app though is to first connect the satellites using wireless backhaul, so they are detected and shown to be online satellites.  Then plug in the wired backhaul cables and hit the SYNC button (a loop condition will occur if you don't) and tell the app to discover new satellites.  It sometimes hangs on to the prior discovery of the satellite and will display it as online but not report there being one on the web page.

The app is not well written, and I think even the logic in the devices is not aware of state changes when things get plugged in or changed.  The logic of the app also seems to be, satellites are ONLY connected if they are connected wirelessly.  All of this is pretty dumb for such a long-established product...

Not that I think these are factors, but my RBRE960 is running in AP mode at firmware level   V6.3.7.5