Auto-VoIP OUI Table Ignored

Hi

I have a GS748Tv5 that I have set up a VLAN to route SIP traffic to dedicated internet access point (the internet access point is also the DHCP server for the SIP phones). This was done to prevent a double NAT situation that was causing problems with the call quality.

I'm using OUI-based Auto-VoIP which is enabled on 2 ports.

Most of the network, connected via another "dumb" switch works perfectly. The phones are identified via the OUI table and routed to VLAN 2 as expected.

The other part of the LAN is connected via a WAN2 port on another router (don't ask) but the OUI filter fails to recognise the phones pn this part of the network. However, if I use the "MAC Based VLAN" add the full MAC addresses and add them to VLAN 2 - they are identified correctly and the obtain an IP address from the correct router.

Any ideas as to why they wouldn't be picked up by the OUI filter when the MAC address is obviously reaching the switch in order for the MAC Based VLAN to route them correctly?

Thanks