[Serusers] failure_route is applied also after CANCEL

I have a problem with redirection to voice mail. If caller hangs up, the CANCEL hits SER and the call is cleanly terminated. SER however continues to failure_route after timeout of the initial INVITE which results in an empty message generated by the voice mail server. Does anyone know how to deal with this? Thanks, Adrian if (is_user_in("Request-URI", "voicemail")) { setflag(3); }; if (!lookup("location")) { xlog ("L_INFO","Location not found"); } else { if (method == "INVITE" && isflagset(3)) { xlog ("L_INFO","Flag3 is set, try voicemail after timeout"); t_on_failure("3"); }; }; xlog ("L_INFO","Relay to destination"); xlog ("L_INFO", "%rm from %is: %fu -> %ru\n"); t_relay(); -------- failure_route[3] { revert_uri(); xlog ("L_INFO","Forward to voicemail (failure route 3)"); exec_dset("/etc/ser/serredir.py voip_voicemail ;echo>/dev/null"); append_branch(); t_relay(); }