I've tried with the new code and i get the same errors in the log :
2021-06-02T18:43:29.662320+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <script>: Before filter_body 2021-06-02T18:43:29.662548+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:275]: parse_sip_header_name(): invalid end of header name for [--unique-bound] 2021-06-02T18:43:29.662733+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [pplication/sdp] 2021-06-02T18:43:29.662922+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:236]: parse_sip_header_name(): invalid start of header name for [#015#012v=0#015#012o=- 184] 2021-06-02T18:43:29.663170+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [v=0#015#012o=- 18455] 2021-06-02T18:43:29.663358+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [o=- 1845520355] 2021-06-02T18:43:29.663535+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [s=-#015#012c=IN IP4 ] 2021-06-02T18:43:29.663709+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [c=IN IP4 212.1] 2021-06-02T18:43:29.663924+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [t=0 0#015#012m=audio] 2021-06-02T18:43:29.664153+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [m=audio 26376 ] 2021-06-02T18:43:29.664333+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [a=rtpmap:101 t] 2021-06-02T18:43:29.664538+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [a=rtpmap:96 CL] 2021-06-02T18:43:29.664718+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:236]: parse_sip_header_name(): invalid start of header name for [#015#012--unique-bou] 2021-06-02T18:43:29.664897+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:275]: parse_sip_header_name(): invalid end of header name for [--unique-bound] 2021-06-02T18:43:29.665119+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:266]: parse_sip_header_name(): invalid header name for [pplication/ISU] 2021-06-02T18:43:29.665323+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:275]: parse_sip_header_name(): invalid end of header name for [Content-Dispos] 2021-06-02T18:43:29.665607+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:236]: parse_sip_header_name(): invalid start of header name for [#015#012#001] 2021-06-02T18:43:29.665864+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:236]: parse_sip_header_name(): invalid start of header name for [#001] 2021-06-02T18:43:29.666135+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <core> [core/parser/parse_hname2.c:275]: parse_sip_header_name(): invalid end of header name for [--unique-bound] 2021-06-02T18:43:29.666341+01:00 dev_sbc_a_vts01 /usr/local/kamailio-5.4/sbin/kamailio[21625]: ERROR: <script>: Filtering failed