WIFI Calling Preferences Being Forced to Cellular Preferred

Went to the T-Mobile store on 10/20/20 to get the two "new" phones I was promised.  Only one phone was there and it was a refurb despite my specifically being told it wouldn't be.  I passed on the refurb.

The district T-Mobile manager was there that day.  He called T-Mobile from the back room where I couldn't hear and came back with a proposed solution:  disable 5G.   I put my phones back to LTE, disabling 5G.   The WIFI Preferences optimization notifications continued incessantly as before.  Actually I noticed that that the phone was actually bouncing between WIFI Preferred and Cellular Preferred settings, as others have described.   I had been setting it to WIFI Preferred and observing it being flipped to Cellular Preferred.   I did not realize that it would also optimize to WIFI Preferred, although much less often than to Cellular Preferred.

Interestingly, a new software update installed to my phone early in the morning on 10/21/20, which was the second update I received during the month of October.   For the rest of the day my phone continued changing the WIFI Calling Preferences just as it had before and making frequent notifications.   But by the next morning, the behavior abruptly stopped and both of my phones now seem to be working normally for the last six days, despite WIFI Calling being left set to Cellular Preferred and my being in a very weak signal area.   Hmmm.  

So everything seems good now for both phones.   Hopefully, I'm not celebrating too soon.   I might eventually reenable 5G and see what happens.

I'm guessing there may be some kind of learning going on where the phone now might be figuring out where I spend most of my time and connect to WIFI.   I wish there were a technical explanation somewhere about what really goes on "under the hood" with WIFI Calling, what the issues have been, and what fixes or other changes have been implemented over time.

I will post back if problems reoccur.