Seems not an isolated issue: http://www.androidpolice.com/2017/12/24/android-8-oreo-may-causing-wi-fi-connection-problems-mesh-routers-like-netgears-orbi/

Same issue even with the beta firmware.

Sadly, ip address reservation didn't fix the issue, will try the beta firmware too.

Meanwhile let's see, i've set ip adress reservation for my Nexus 6p, wondering if it's something related to dhcp that can be fixed this way.

I'm starting to think that issue comes from Android 8.1. It's happening since i updated my Nexus 6p to it. Indeed also some netgear devices seem affected: https ://...

I'm having the same issue since some days. The only solution is to switch off/on again. Have also tried to disable pretty everything in the config, using different dns, and reset the device.