Hi,
kamailio 5.2 branch has a commit
09ac3e47ef79dbd599b7dec5b84ae3b792f025ed cherry picked from master branch.
It makes sense for master because get_send_socket2() behavior has
changed and function became started and also there were some patches to
propagate connection it to uac structure.
5.2 kamailio takes the first interface for TCP/TLS/WS connections and
then finds existing tcp connection matched by ip:port, but when the
patch is applied connection lookup fails and kamailio can't forward
in-dialog messages.