FIX - SIP calls that are hung up (with BYE) after establish has been started (post ACK'ing the OK) but not finished get stuck on the hyrbrid
FIX - Outbound sessions with a repeated call-ID must replace existing call
FIX - Handset devices (non A/S devices) which disappear / go offline during a call setup are left unusable when the device eventually comes back and re-registers
