Blind transfers on Polycom VVX

Hello,

Attempting to do a blind transfer from a VVX phone but it just hangs up.
In PBX console I do see this notice being logged when it happens: NOTICE[4191]: chan_sip.c:21028 attempt_transfer: SIP Transfer attempted with no appropriate bridged calls to transfer

Tried couple different firmwares for the VVX's (4.1.4, 4.1.8, etc with same results on all of them)
We're currently running Asterisk 1.8.7.1

Any help would be appreciated.

Thank you.