Duplicate packets from SIP phones


I’m experiencing echo, my own voice, and a bit of noise on outbound calls to the PSTN from all SIP phones. Both Yealink and Grandstream. Using an analog phone and FXS port on the system results in crystal clear test calls. Phone to phone calling is crystal clear.

A pcap shows duplicate response packets from phone to PBX. One packet from asterisk, phone responds with two packets using the same sequence number.

Snippet of Pcap is here:

I’ve tried isolating the PBX and single phone for testing. Different phone models, brands, different switch models, etc.

Does anyone have an idea? Asterisk 11.7 and FreePBX.

Thank you