I'm using the latest, 49873, and it has been solid. No problems, 160MHz. wide backhaul channel, no disconnects, no drops of the backhaul to 2.4GHz., no flashing blue lights during normal operation, etc.
When you go to the remote node using the Asus Router smart phone app, what does it show for the connection between the router and remote node? Backhaul dropping to 2.4GHz. may indicate that the nodes are too far apart. When I look at that, I see that the connection quality is "Great", and the strength is -64dBm...the backhaul signal strength at the remote node here varies between -58dBm to about -64dBm.
Anyways, I'd suggest not allowing any of the channel selections or channel widths to be auto. Start with picking a channel on 2.4GHz., with a channel width of 20MHz. And pick a channel for the 5GHz-1 and 5GHz.-2 radios. For channel width on 5GHz-1, leave it on 20/40/80, channel 44 is a good one here. For 5GHz-2, I enable 160MHz., using channel 149 as the control channel. This gives me 160MHz. backhaul, using the UNII-4 channels. If you want to be more stable to start with, you can disable 160MHz., and just use channel 157 or whichever one works for you as your control channel...and again, leave the 20/40/80 channel width selection. When you look at the wireless log, it will show you how things are connecting, with what channel widths, length of time for each connection, etc. A good way to get an idea of what's going on with your wi-fi devices. The backhaul is there, too, of course, so you can look at what it's currently doing, as well as how long it's been doing it.
I also separate the 2.4GHz. and 5GHz. client radios into two separate SSID's, rather than just using one. That seems to work better here, as well as allowing the few IoT devices that I have to definitely be put on 2.4GHz.
These settings work for me, like I said 49873 has been solid for me for about a month. Everything's working great, including the two new Nest security cameras...they're on 2.4GHz.
