Jitter-bug
Voiopmonitor sniffer 16.0 fixes jitter calculation for huge jittered calls. The jitter was always lower than it should be compared to wireshark and RFC due to rounding issue in the code.
Here you can see simulated jitter/loss call comparison processed by sniffer < 16.0 where avg jitter is 39 for caller and 42 for called which is wrong - also see those two charts and PDV differences
This picture is CDR processed by sniffer >= 16.0