Cisco SPA508G question

So about a year ago I deployed a Cisco UC320 phone system with approx. eight SPA508G phones. Using a SIP trunk from Broadvox, no POTS lines.

A problem has been identified and it is pretty serious. If one of the users is transferred a call via the AA or another user in the middle of dialing a phone number at their extension, and completes dialing that phone number, then the person being transferred-in becomes an unintended third party on that call. They can hear the conversation between the extension to which they were xferred, and the number that extension was dialing, for about 15-20 seconds. After 15-20 seconds, they are transferred to the voicemail for that extension.

I can duplicate this, it happens every single time I follow that sequence.

Now, I posted over at the Cisco forum but do not expect them to respond, they’ve given-up on the UC300 and UC500 series of gear, apparently. They discontinued the stuff right after I ordered it.

So I figured I may have to replace the UC320 with a FreePBX box. But before I did that, I wanted to make sure:

(1) That this isn’t a problem with the SPA508G phones themselves. If there is some setting on the phone I need to adjust and replacing with a FreePBX will just cause the problem to occur on the new box.

(2) If the problem is with the UC320 itself, and (SUPER LONG SHOT) if anyone here knows of a fix, I’m all ears. I can install a FreePBX box but it will take some time and $$$ and I’d just as soon avoid it if possible.

Ugh Cisco, ugh.

And here is the thing: Cisco wants me to buy a support contract to talk to them. That seems insane given the long-shot that they’d have a solution they haven’t posted somewhere.

Any input would be welcome. Feel free to pile-on for me even selling a Cisco UC320.