So I recently purchased, and set up, a 3-device Deco S4 mesh system. I have the 1 main device, 1 device connected via gigabit ethernet, and the 3rd is connected via a wireless backhaul.
If my internet goes down for any reason (my home internet is unstable. Our whole street is. Thanks mediacom..) then when it comes back up, the 2 wired devices just keep on keeping on, no resets needed, but the one with the wifi backhaul will not have a connection, and will have a red led. I then unplug it, and plug it back in. A few minutes later, it's all good, and has a good connection to it's brothers.
This annoys me, mainly because it is providing service.to our garage and and much of the yard, as well as my wife's new smart washer. Which is in said garage.
I've tried swapping the two satellites, to rule out a bad one, but it doesn't matter which one uses the wifi backhaul. Whichever one does will nearly always have reconnection issues when the internet goes out. Why? It's not like the wifi itself goes down. Just the connection BEYOND the main router. All devices still ON the network should be able to talk to each just fine, whether the outside connection works or not!