[BUG] SDP is not updated on re-INVITE or late offer via b2b

[devoxy1]

I'm testing transfers with b2b on opensips+rtpengine setup.
The scenario is:
A -INVITE--> Opensips -INVITE--> B
A <-200OK-- Opensips <-200OK-- B
------ Opensips <-REFER/302-- B
------ Opensips --INVITE-> C
------ Opensips <-200OK-- C
------ Opensips --BYE-> B
A <-re-INVITE-- Opensips --re-INVITE-> B

I'm using rtp_relay for SDP processing on new leg. Here is brief config i use:

route{
     rtp_relay_engage("rtpengine", 0);

    ...

    if (!has_totag()) {
        b2b_server_new("caller",,$avp(extra_hdrs),$avp(extra_hdr_bodies));
        b2b_client_new("callee", "$ru",,,,$avp(b2b_hdrs),$avp(b2b_hdr_bodies));
        # initialize B2B session
        xlog("L_INFO","[$ci] [$rm] [ROUTE] B2B logic key: $b2b_logic.key");
        b2b_init_request("refer");

        exit;
    }
}
    ...

route[b2b_logic_request] {
        if ($rm != "REFER") {
            # for requests other than REFER, no special actions needs to be done,
            # just pass the request to the peer
            xlog("L_INFO", "[$ci] [$rm] [B2B_LOGIC_REQUEST] Passing request - From-tag: $ft, To-tag: $tt");
            b2b_pass_request();
            exit;
        }

        xlog("L_INFO", "[$ci] [$rm] [B2B_LOGIC_REQUEST] BLIND TRANSFER - Refer-To: $hdr(Refer-To)");
        xlog("L_INFO", "[$ci] [$rm] [B2B_LOGIC_REQUEST] Refer-To: $hdr(Refer-To)");

        xlog("L_INFO", "[$ci] [$rm] [B2B_LOGIC_REQUEST] PEER: $var(peer) CLIENT: $var(new_client)");
        # Создаем новый INVITE третьей стороне
        b2b_client_new($var(new_client), $hdr(refer-to),,,, $avp(b2b_hdrs), $avp(b2b_hdr_bodies));

        # bridge the referrer's peer with the referee
        b2b_bridge("peer",$var(new_client),,"notify,no-late-sdp");
}

route[b2b_logic_reply] {

    if ( t_check_status("30[12]") ) {
        xlog("L_INFO", "[$ci] [$rm] [B2B_LOGIC_REPLY] DIVERSION - From-tag: $ft, To-tag: $tt");

        ...

        b2b_client_new("diversion", $var(redirected_contact),,,, $avp(b2b_hdrs), $avp(b2b_hdr_bodies));
        b2b_bridge_retry("diversion");
    }

    b2b_handle_reply();
}

OpenSIPS version you are running

version: opensips 3.4.9 (x86_64/linux)
flags: STATS: On, DISABLE_NAGLE, USE_MCAST, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, HP_MALLOC, DBG_MALLOC, FAST_LOCK-ADAPTIVE_WAIT
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535
poll method support: poll, epoll, sigio_rt, select.
git revision: 448fdf959
main.c compiled on 12:37:50 Nov 19 2024 with gcc 11

Describe the bug
I encountered and issue with incorrect SDP on re-invites on new leg either using REFER or 302 Moved for transfers.
In the scenario above INVITE from A to opensips and new leg on B is processed correctly, SDP is updated and rtpengine's IP is set.
New leg to C is created with correct SDP, rtpengine's IP. However if reINVITE from A comes later to update session SDP is not updated and IP of A is passed to C. The issue is present when using REFER with no-late-sdp or 302 Moved. When using default REFER behavior with late offer SDP in ACK is not updated by rtpengine's IP as well.

To Reproduce

1. Call from A to B via opensips
2. B sends REFER to transfer the call to C
3. Opensips accepts REFER and send INVITE to C
4. C accepts the call
5. Call with B is hung up
6. Opensips sends re-INVITE to both A and C with incorrect SDP

Expected behavior
re-INVITE sends rtpengine IP in SDP

Relevant System Logs

OS/environment information

• Operating System: Ubuntu 22.04.1 LTS
• OpenSIPS installation: git

Additional context
There was an issue opened by me with earlier version before which was closed. The problem persists.