WIFI Calling Preferences Being Forced to Cellular Preferred

Bottom line primary trigger causing "Cellular Preferred" changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. This in turn blows for us all because it is implemented into almost all newly developed/updated apps to be allowed in the Google Play Store, even the built in Android app that senses input from a simple touch of your touch screen and keyboard apps cause wifi scanning to momentarily take place, had mine changing it seemed 50% of the time swiping my screen to unlock. The standard Android settings menu allows you turn off wifi scanning so they make it seem but this toggle only disables wifi scanning features at user level installed apps, not wifi and GPS scanning for system based ones provided by Android/vendor/Google.