TM should be able to different between the 200 reply to the locally generated CANCEL and the 200 OK for the relayed INVITE. You shouldn't have a problrm. Can you post your config?

From: James Lipski via sr-users <sr-users@lists.kamailio.org>
Sent: Saturday, October 7, 2023 9:01:03 AM
To: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Cc: James Lipski <jameslipski@protonmail.com>
Subject: [SR-Users] Re: CANCEL first, then INVITE.

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Hello,

Thanks for the reply. Would there be a way to prevent a situation where kamailio would receive 2 200OKs from being received (1 200OK for CSeq INVITE and 1 200OK for CSeq CANCEL)? As of right now, at least with my test configuration (using the skeleton configuration) it seems to be easily replicable. I'm trying to prevent a situation where "t_set_fr" and the UA's internal timeout fire at the same time causing 2 200OKs from sent by the UA (as described on my previous message).

Thank you.