FWIW I had similar weird connection issues with the ET8 and v1 XT8.
The v2 XT8 hasn't been a real problem for me though. Good to hear you found a fix with the Deco series...
Wanted to follow up in case anyone else hits this.
Turned out to be a bad router...exchanged the set and ended up with V2 XT8 hardware. Tested for about two weeks now without the quirks mentioned. No random WiFi connected but not routing to the Internet so you have to switch WiFi on/off on...
I've got some puzzling behavior with a pair of XT8 mesh routers. They're set up to backhaul on the 5-2 band.
When I'm near the main router, it keeps connecting me to one further away on the 2.4ghz band. Turning WiFi on/off doesn't change this behavior.
So out of curiosity, I tried turning off...
Sorry...same as OP.
I.e., WiFi seems ok for a while and then it stutters/lags for a while, then goes back to normal. So I was wondering how to tell if I have v1 vs. v2 hardware. I also tried an ET8 pair with the same behavior.
I'll start up a separate thread because AI mesh behavior is a bit...
I'm curious how you'd be able to tell as well.
Also, FWIW, this random lagginess also happens w/ the ET8. Tried that initially and returned it because of the random lagginess. Same issue w/ the XT8 I replaced it with.