i have this problem,..
the unique issue is that if my spouse calls me, we drop to LTE.
if I call my spouse, we stay on wifi.
There is something with the device (even though they are both iphone 11 pro max) running now 13.4.1 and updated directly via a macbook through cable not via the air with a minor update file, this should have been the full update.
I have also
- toggled facetime
- logged out of icloud and back in
- reset network settings
- deleted and reinstalled the facetime app
When we try this we are within 6 feet of the router, that is WiFi 6 and working with strong signal quality. on my internet service provider, I get atleast a solid 350-400 MB per second download speed and upload is good.
The device with the issue (my spouses) when making a call stalls and thinks about the process... Its like its sampling the service and continues on with wifi until we connect. then it drops to LTE...
For me if I call my spouse the call immediately rings the device and we stay on wifi indefinately.... So there is something within the software I feel that has sampled service that is not registering it correclty causing the phones to drop to LTE. My hardware is working 100% perfect, here the other has this issue and impacts all callers.
I'm not sure what other options I have to have the phone do a item without wiping the phone (which I really don't want to do).
Somewhere there must be something that apple can clear out but with stores closed to review this its really confusing and complex. Unless they have different modems or chipsets which is leading to the issue of select devices having issues and others not... As the models only differ by color. Mine space gray, the other gold. Again same model, same memory specs (256 GB) , on the same wifi and running the same iOS version.
So this has to be a software glitch for speed and performance testing for which I see the delay occur when making the outbound calls on the impacted versus non-impacted device within our home