NOTE: In this scenario, a Cisco Call Manager system sent a call to IPCM.
The outside caller pressed a button to select an IVR menu option (option 1) and then waited to hear a prompt for the next input block (Get string block). No prompt was heard and after about 10 seconds and then the 3rd prompt was heard instead of the 2nd prompt.
When the wireshark captures was checked, there was only 1 DTMF sent (RTPEvent packet) but in checking the application log in IPCM, 2 inputs for the number 1 were seen/processed.
After the SIP trunk settings on the Cisco side were modified to enable Media Termination Point Required, the DTMF tone worked as expected and the entry no longer bled over into the next input/menu block.