RBK23 changes topology and satellites drop.

If both remote locations are wired to the modem location with Cat6, you are better off to purchase an inexpensive gigabit switch, connect the one LAN port on the RBR20 to the switch and both satellites to the switch.  (Not having a prewired house, I have not done this myself.)  My understanding is that you should first sync the satellites using the WiFi backhaul so that they 'know each other', then move to the remote location and connect over ethernet.  It may take quite some time to transition to ethernet.  Disable Daisy Chain on the router.  That should solve the topology problem.

Devices decide what access point offers the best connection and when the connection has degraded to the point that they want to switch.  It is a continuing issue on the forum.  People want the Orbi to say, "hey dummy, you would be better off connected over there, so move already."  Some devices just make dumb decisions.  With things that cannot move, such as TV's, using an ethernet connection back to that switch is a great solution.