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.

I have the exact same problem on my samsung s10e android software version 10.  The problem started very recently immediately after an update.  For over a year the phone was working fine.  Now I set my preferred network to Wifi (because there is very poor tmobile coverage at my house) I have excellent wifi signal.  After a few minutes my phone alerts me that it has updated my preference to Cellular.  There is thread from over a year ago reporting the same problem but the thread is marked solved and I don't know why.  A lot of people started posting on it recently saying they started having the same problem in the last two months.  Does Tmobile think the problem is fixed because it most certainly is not.  

I find it very interesting that TMobile has not responded to this. I had the same issue with my Samsung A71. I specifically moved to TMobile for the 5G capability which is not worth the letters that make it up. Why be sold into a 5G capable phone (for obvious money) when the service is not consistent. I too disabled 5G and have so far had limited success with the results. It still toggles back and forth but instead of every 10 min, I am down to about 5 times a day...success?!?! maybe. BTW, 5G was 50% speed of my old Samsung S10 on 4G on other carrier.

@fireguy_6364, I do not have a FB or Twitter account to deal with them. I have also tried calling and support was pretty useless. I had to troubleshoot through the internet to figure out to turn 5G off.

Same promelem for me on the note 20 ultra. I constantly have to switch back to wifi preferred at work because I get no signal. 

as of the one UI 3.0 / android 11 update, there is now a solution for this that seems to work 100% of the time via tasker without any further interaction from the user. one profile and one task and it will keep you on wifi preferred...i've had this running for over a week now and it has worked perfectly.

https://www.grecobon.com/2021/01/unlocked-galaxy-s20-wifi-calling-issues/

tldr - since the android 11 update, there's now a custom system setting that controls this that we can monitor and change via tasker. the custom setting you're looking for is wifi_calling_preferred1. create a tasker profile that will automatically set it back to wifi preferred as soon as it changes to cellular preferred. my tasker profile and action are at the link above, as well as on taskernet (link in the blog post).

Same issue here. The problem seemed to first appear about 6 0r 8 months ago or so after an update. I then starting missing many texts and calls both coming and going…..very frustrating! My wife was having the same problem with her Note 8. As with others here, the T-Mobile coverage here is marginal and we depend on the WiFi calling for the majority of our communication…...not anymore! We were actually due for new phones anyway so I thought, rather than try to fix the problem, well, it must be our old phones. We upgraded to an S21 Ultra and a Note20 Ultra…..$2300 worth of new phones! Things seemed good for a week or so….then we seemed to be missing texts and calls! Our phones were again swapping to "cellular preferred"! This is completely unsatisfactory!!!!  8 years ago I swapped from Verizon to T-Mobile (even though the Verizon coverage was better) because I believed in the T-Mobile customer service and extra perks. But if the phones can't perform their basic functions, and, T-Mobile refuses to resolve this issue, it may very well be time to go back to Verizon! 

I am breaking my promise. I am making one more post as a T-Mobile customer.

I am leaving T-Mobile for CREDO Mobile. I do this with regret. When I joined T-Mobile it supplied voice reliability through Wi-Fi calling. As long as my Wi-Fi was working, my phone used Wi-Fi calling with no problems. If I had any problem, T-Mobile Customer Care came up with the solution.

This all changed with a software upgrade two years ago. Wi-Fi calling became unreliable, and my voice quality suffered. It kept getting worse. I started losing calls.

Over the past months I have put a lot of effort into trying to get T-Mobile to fix the problem. Calls to customer care did not provide a solution, and a promised callback from technical support never happened.

A letter to customer care at headquarters resulted in a call from a customer care rep, but my cell phone quality was so bad we had to switch to my land line, and then to emails. Still no solution, although I was offered a discount on a new iPhone.

I then searched for T-Mobile USA management and found Callie Feld, executive vice president and chief customer experience officer. I sent her a letter detailing my experiences and asked for help. I waited a week and a half, then sent her another letter yesterday saying the wait was over, I was switching to CREDO.

T-Mobile customer care is the main face of T-Mobile to its customers, and it is the face they see when they have problems. When customer care fails to provide the needed support, T-Mobile looks bad. With this issue T-Mobile looks incompetent.

T-Mobile should be able to query its problem database to determine how many customers have this issue, how long they have experienced this issue, and the models of the phone that are having this issue. Customer care should be sharing this data with product support. They should be saying 'Albuquerque, we have a problem.'

So I will say it. Albuquerque, you have a problem.

Same here, Galaxy s8+. Very annoying, I'm guessing it's deliberate so tmobile can get you to use their network as much as possible. Pisses me off when working from home where my cell signal is basically between zero and two bars. Drops calls all the time. When you select wifi preferred it should mean use wifi whenever you have it goddam it, not act like a smart-ass and keep 'optimizimg' it so that you cannot make or receive phone calls and miss messages. 

Same happens on my note 20 ultra, seems like I have to switch it back to wifi preferred at least once a day while I'm stuck at home this year. Actually making me consider going back to Verizon when I upgrade phones again because I get poor cell service just while inside my house, thus T-Mobile's implementation of this feature makes using a basic phone function a daily fight that is wearing my patience thin.