Rebooting the hub and extenders makes no difference, only turning off the 6Ghz in the Guest WiFi stops this.
I have also had major issues trying to get 80 WiFi devices onto my new network as they kept going offline or online with no internet connection and I eventually discovered that if the WiFi SSID name in either the main or the compatible networks has either a space or an underscore in it, the problems occur on both. So I changed the SSID and logon on every device to simple "Home" and it works fine. "Home_1" and "Home 1" cause problems.
