What could cause this type of PCAP?

[greychain]

Customer is finding some calls the audio quality is not good with internal calls, they have 2 separate 3CX PBX's bridged together. Going through a PCAP I found some odd things, this being one of them. Also a reference to a RTPType-121, RTPType124.

This is a singe RTP stream with 3 distinct caller groups on it.

Latest V18, upgrade a week or 2 ago

 

[Nathan@Voxtelesys]

Do you have "PBX delivers audio" enabled on the phones? Are phone ports incremented and not overlapping? Any Firewall/Router changes recently?