miconda left a comment (kamailio/kamailio#4140)
I pushed a commit to change TM_DELAYED_REPLY to a modparam `delayed_reply`, because it has the purpose of allowing the config writer to send its own response in case of tm request processing/forwarding failures.
Can you try to use:
- https://www.kamailio.org/docs/modules/5.8.x/modules/sl.html#sl.f.send_reply_...
instead of `sl_reply_error()` in your config?
The case has to be handled somehow automatically, the above suggestions are more to figure out if that is the real issue, then code something for it.