I thought we had this issue resolved. I turned off NAT traversal.
Extension to extension calls work fine
We can dial and receive calls, but the audio is not being passed across the VPN

Setup
Local Router 10.1.10.x
Site to Site VPN via Cisco RV320
Remote location 192.168.3.x

Phones in remote site
IP address of 10.1.10.x
Gateway is IP address of Router at local site
Nat Traversal Disabled
Sip Server is Local SIP server 10.1.10.x
RTP & Self SIP ports are set to even numbers out of range or conflict

Any idea what I am missing?