System is a MICS 7.0 with CP100 3.1. CP100 is accessible through the LAN and configured for CallPilot mode instead of NVM. PRI with 8 channels / 10 DID's (line 157 +) and 3 I/C on each set (7316E). DN 221-228 all have VM boxes with matching box numbers.

Regardless of the origin of the call (I/C or outside line), when using F986 to transfer the caller to a VM box, the set prompts for the mailbox, flashes "Call Transferred" but then pops back to:

221 (or whatever VM box transferred TO)
DIR QUIT

and this stays on the set display until the caller disconnects. The caller is prompted with "Please enter the mailbox number or press the # sign to use the directory". I know it is trying to get to a VM box because if I try to transfer to a non-existent or uninitialized VM box, I get the expected "Invalid Mailbox" or "Mailbox not Init".

Any ideas?