A little over a week ago, I replaced an iPhone 6s for an XR through Verizon. Nothing has changed technically except for the phone change. I primarily use the phone at a specific place in my home office that has a very good wifi signal, but there is a poor cell signal. As a result, for some time I have relied on wifi calling when using the phone in the home office. Before the phone change, call drops were very rare - almost never other than when a person I was calling was driving through a tunnel. As soon as I started using the new phone, there have been a few dropped calls every day. I've gone through a lot of trouble shooting with both Verizon and then Verizon directed me to Apple support and there have been many settings changed, software update and phone completely reset, etc. Verizon says I qualify for their network extender, so that's the next thing to try, and I am still in the period where I can exchange the phone, but wonder if there is something inherently not compatible with the XR.
Although I realize that cell signal strength should have nothing to do with wifi calling there is a very strange anomaly: I have the phone set for wifi calling, and the cell signal normally shows 1 or 2 bars - rarely if ever get as much as 3 bars and never 4 bars. I've noticed every time a wifi call drops, the cell signal shows 4 bars for a few seconds and then it goes to 0 bars. During this time the wifi signal remains very strong, but for about a minute I can't connect on a new call. Some of the Apple tech support people have indicated that is a strange thing to happen, but one Apple sr. tech said that it is totally unrelated to the dropped calls, which I understand is logical, but it still seems like a symptom of a technical problem with the phone. Of course the final blame by Apple is my wifi network is the problem, although never a problem until I changed the phone. My old phone was sent back to Verizon for trade-in so I can't test if it still works the same. Last suggestion by Apple was to go somewhere else where there is a wifi network and test the phone calling from the other network. Not a very practical thing to try with an intermittent issue that may not be seen for hours.
Although I realize that cell signal strength should have nothing to do with wifi calling there is a very strange anomaly: I have the phone set for wifi calling, and the cell signal normally shows 1 or 2 bars - rarely if ever get as much as 3 bars and never 4 bars. I've noticed every time a wifi call drops, the cell signal shows 4 bars for a few seconds and then it goes to 0 bars. During this time the wifi signal remains very strong, but for about a minute I can't connect on a new call. Some of the Apple tech support people have indicated that is a strange thing to happen, but one Apple sr. tech said that it is totally unrelated to the dropped calls, which I understand is logical, but it still seems like a symptom of a technical problem with the phone. Of course the final blame by Apple is my wifi network is the problem, although never a problem until I changed the phone. My old phone was sent back to Verizon for trade-in so I can't test if it still works the same. Last suggestion by Apple was to go somewhere else where there is a wifi network and test the phone calling from the other network. Not a very practical thing to try with an intermittent issue that may not be seen for hours.