I'll try to test all call scenarios tomorrow.
Thanks for the quick fix.
Well, I found a new bug. If the callee wants session-timers and sets the uac as refresher, the ACK on the 200 OK of the session-timer re-INVITE isn't handled correctly. The ACK will be send directly to the contact of the callee. If the callee designated the uas as refresher, all goes well.
Attached a pcap showing this problem (the initial INVITE to the callee is missing for some reason (fragmented?)) and the topos related debugging from the timeperiod.
BTW syslog is getting spammed with ERROR: topos [tps_storage.c:874]: tps_storage_load_dialog(): no dlg uuid provided these are related to locally generated OPTIONS by the dispatcher and nathelper modules.