not sure I understand your comment, but as you can see on my trunk config Im forcing to connect TCP,UDP ports, howerver I´ve changed to only TCP reload and reboot still the same
type=friend
transport=tcp
qualify=yes
promiscredir=yes
port=5068
insecure=very
host=IP LYNC SERVER
fromdomain=IP ISSABEL
context=from-internal
canreinvite=yes