Intermittent issues with calls going directly to voicemail and not ringing the station. Station is not in use, on SEND or forwarded. Station did not lose registration. CM 6.2; Modular Messaging 5.2; 9650 IP Phones and 9641G IP Phones; external calls using SIP; SBC 6.2; Session Mngr 6.2. Cannot trace a call because you never know where it comes from or where it is going. This issue surfaced in a remote location about a month ago and now has shown up in another site. We do not know if more are impacted. Transfer to voicemail is another issue but do not have all the details. Just that one reported when attempting to do this, call did not transfer and they heard a "beep". Thoughts? Anyone seen this?