Mines been ok since moving to the 4601 firmware. But you can also try
creating a guest Wi-Fi network on the xt8s and connect the nest to that
which worked perfectly for me also.
I tried something different yesterday. Created a guest network on the
zenwifi but only connecting to the router and not the mesh network.
Connecting the thermostat to this guest network and it’s been rock solid
so far, no disconnections at all. Will ...
Same issue for me also. Nest App shows as disconnected at random times
throughout the day or has a serious lag when I change the temp of the
actual thermostat. This has only started happening since changing to the
zenwifi ax.