After upgrading the system firmware to R11.5.0.E the CID Prefix functionality for Ring Groups stopped functioning. I still see the prefix being sent to the phone in debugs however the phones still display "Unknown". We use this feature for our Door Phone to differentiate it from other inbound calls. I have tried upgrading the firmware on the phones to the latest release in effort to resolve the issue however that did not work. Is this a known bug and if so, is there a work around to resolve it?
Brian, please reply with a "debug sip stack message" and "debug voice verbose" during one of these calls as well as the 7100 configuration with any sensitive information removed. Also, please confirm the phone models and exact firmware versions they're running. Thanks