I'm using Nokia E71 SIP and while doing calls to Cisco IPCC, I ended up at the "on-hold" when call was transferred from IPCC to voice gateway, and then the call was dropped.

Packet traces shows that when the CUCM transfer the call from the IPCC to the voice gateway, the CUCM signals the Nokia with 'a=inactive', and the Nokia replies back with 'a=recvonly'.