Choppy sound on T32G (PCAP included)

[phuygens]

Dear,

A few months ago we've deployed several Yealink T32G's with one of our customers.
We have several intermittent audio issues.
This is the setup:
- 3CX phone system on site A, +/- 20 phones are located on the local LAN on site A.
- 3CX SBC is deployed on site B, +/- 20 phones are located on the local LAN on site B.
- The choppy sound is on all the phones, but intermittent (at both locations), internal & external calls...

There is QoS implemented on the local LAN and on the 3CX SBC.

I've a PCAP attached on this post.
I've also a PCAP available (made this on de 3CX server) of a whole day (with around 70 phone calls in it, if you need this, I will make it available on dropbox or something like this).

The firmware of the phones is on 32.70.0.221 (last 3cx supported firmware).

The VAD, CNG & echo cancellation is enabled.
The jitter buffer is as default: adaptive, min 0, max 300, normal 120.
Should I change this to fixed 120,120,120?

Thanks for support!

Kind Regards,
Pieter