RBS750 no longer connects

I have an RBR750 and a pair of RBS750s that have been working flawlessly for a year and a half. The RBS750s are running firmware version V4.6.5.14. One of the RBS750s (MAC *A1) now reports as disconnected (I checked it's firmware version using a wired connection and it allowed me to log in and check.). Rebooting everything didn't reconnect it. My next reconnection try was to connect it to the wired network that just happens to be right next to that particular satellite. Once I did this the satellite that had been connected (MAC *19) started reporting that it had a wired connection in the Orbi app (version 2.17.0.171 under iOS), while MAC *A1 still reported as unconnected. I powered down MAC *19 and ended up with no connected satellites (showing that the app reporting this satellite as having a wired connection was wrong). I powered MAC *19 back up and now everything reports correctly (MAC *19 is connected wireless now), but MAC *A1 is still offline.

I've tried Syncing them using the buttons on the router and the satellites. I've tried "Add a new satellite". I can't get MAC *A1 to connect. Both satellites respond to pings from computers on the network (the wired connection has much lower round trip delay), but MAC *A1 still won't connect to the RBR750. Any other ideas?

Is the app getting confused about wired/wireless connections old news? How did it know about the change to a wired connection on a satellite it claims isn't connected?