We’ve run into really interesting issue while testing Kamailio with sipp (15 CPS, 300 calls - 1 failed call, more CPS - more failed calls) with topos involved.

And at some point Kamailio starts to send 2 packets on received INVITE. 1 - with topos applied, 1 - with not.

Main problem is to collect logs at this point, cause load is really high.

Is it possible some internal race condition while topos involved?

PCAP is attached.

I’ve made a picture to illustrate a bit an issue