hi, after 1-1.5 week after update problem solved somehow by itself. i think my network provider updated their network firmware (MTS 41.0, was MTS 40.0) or local mobile modem firmware somehow here in Moscow, Russia! or probably apple noticed that their servers send a lot of stuff to phone and back and block it/reroute it....i still don't know exactly, i'm pain free for 2 days only with ring working. so it's 100% not a technical problem with your ring knob. apple support too was unable to help and advised to pay money for testing in local technical service here in Moscow....
so i think problem is in your mobile network operator!