Yes, trunk is disconnected on 29 seconds, because it execute hangup
Executing [h@restrictedroute-c4ca4238a0b923820dcc509a6f75849b:1] Hangup("PJSIP/4238-00000082", "") in new stack.
How about by disabling reinvite on PJSIP trunks by setting timer=no?
Since the are post with similar issue, but with different disconnected time.
May be it could help.
Workaround via «Admin»→«Config Edit»→pjsip.endpoint_custom_post.conf (replace myTrunkX with name of your pjsip trunk from «Connectivity»→«Trunks» or CLI “pjsip show endpoints”… note the (+) which indicates add this to an already present config.
pjsip.endpoint_custom_post.conf
myTrunk1
timers=no
timers_min_se=28800
timers_sess_expires=28800
link