Polycom vvx 500 audio issues

Just getting into the vvx series. Calls call out to trunk and internally fine on asterisk 11 from the polycom vvx500 to a spa504g; however, on asterisk 1.8 (I know… it’s an issue with the trunk provider, at least at the time we installed), the polycom vvx 500 calls out to the trunk just fine–no audio issues–but calling internally to polycom 331 and 450 phones, there’s no audio. Anyone else run into this issue?

These ditros were PIAF