"even with the beta and disabling one of the receiving cores"
Yes I did, and rebooted just to make sure it stuck. I've never seen this issue and I have several FreePBX installs behind EdgeRouters, and I actually ran my own home office install behind the same ERPOE that's at the client location.
And our FIOS is static IP. Was installed ages ago when it was still Verizon. They gave us just an Ethernet handoff... it runs to some equipment closet in the industrial park where this client is... not your typically Actiontec gateway.
What's really strange is how this only affects a minority of the calls, and it's always 10% packet loss.... and from what I gather it's ONLY outbound calling that's affected.
Baffled and bummed