[SR-Users] Kamailio PCSCF route logic

Hello community, We made some modifications to Kamailio PCSCF sample cfg file, so when PCSCF receiving an tcp SUBSCRIBE message it add ;transport=tcp to the end of Contact URI. Below is what we added the route block right after if (is_method("INVITE|SUBSCRIBE")) logic if (is_method("SUBSCRIBE") && proto=='tcp') { $var(original_contact_header) = $ct; $var(new_contact_header) = $(var(original_contact_header){re.subst,/(.*:.*)(>);/\1;transport=tcp>/g}); remove_hf("Contact"); append_hf("Contact: $var(new_contact_header)\r\n"); msg_apply_changes(); } We did see the ;transport=tcp been added but we also seeing a bad line ;alias=[...] is added before the To: line [cid:image001.png@01D84375.8D109B20] Does anyone know what function might cause this ;alias been added before To: line? BR, Weiqi