When using TAPI to transfer a caller to an internal invalid number, the results are different depending on when during the "invalid number, please hang up and try again" message playback you cancel the transfer. If we drop the call to the invalid destination a 8-10 sec into the message, then attempt to unhold the transfered party we do not get an IDLE on the line we are transfering from returned for about 30 sec. If we perform a DROP just as the message starts playing, or after the message has finished and we get reorder tone the IDLE comes back immediately.
Attached failure & success logs from TAPI Browser, along with Cisco TSP log.
Most likely this will need further analysis from BU engineer to determine the root cause. You'll need to provide more logs and device call info (DN/timestamp, etc..) along with Cisco CTI/Call Manager Traces (Gathering CTI/CM (SDI/SDL) Traces). Please contact your Cisco account team if you need to escalate this for further analysis. Thanks.