[Users] "invalid cseq for aor" in replicated registrations

Hello all, I have a question about replicated registrations. Server1 sends an authenticated REGISTER to server2. The script looks like: if (method=="REGISTER") { if (src_ip==server1) { # Handle replicated registrations. No need to authenticate, just save. if (!save("location")) sl_reply_error(); } else { # Digest authentication if (!proxy_authorize("", "subscriber")) { proxy_challenge("", "0"); return; } if (!check_from() | !check_to()) { sl_send_reply("400", "Bad Request"); return; } if (!save("location")) { sl_reply_error(); } # Send a copy of this registration to the other proxy t_replicate("sip:server2:5060"); } return; } On server2 I get this message: ERROR:registrar:update_contacts: invalid cseq for aor <...> But I don't have the same message on server1. If the cseq is invalid then how come server1 saves it successfuly and then replicates it to server2? thank you George Disclaimer The information in this e-mail and any attachments is confidential. It is intended solely for the attention and use of the named addressee(s). If you are not the intended recipient, or person responsible for delivering this information to the intended recipient, please notify the sender immediately. Unless you are the intended recipient or his/her representative you are not authorized to, and must not, read, copy, distribute, use or retain this message or any part of it. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses.