Update from my last conversation with Apple support:
There will be a carrier update soon to fix the issue. It is caused by an incompatibility between the current carrier version and the new iPhones, but only for some operators. I am on Sky, which is O2 in reality.
Another symptom I noticed is when toggling from 4G VoLTE Off to 4G VoLTE On, I get a message stating that This mobile network has not been certified by the carrier for VoLTE on iPhone. The support analyst stated that this was linked to the issue but I’m not sure how much it is a factor.
No timescales on when to expect a carrier update, and I can’t be arsed to spend time on the phone complaining to Sky, going over all the issues again, to get a date for the update.
There will be a carrier update soon to fix the issue. It is caused by an incompatibility between the current carrier version and the new iPhones, but only for some operators. I am on Sky, which is O2 in reality.
Another symptom I noticed is when toggling from 4G VoLTE Off to 4G VoLTE On, I get a message stating that This mobile network has not been certified by the carrier for VoLTE on iPhone. The support analyst stated that this was linked to the issue but I’m not sure how much it is a factor.
No timescales on when to expect a carrier update, and I can’t be arsed to spend time on the phone complaining to Sky, going over all the issues again, to get a date for the update.