Cancel after a 486 Response


I´ve been trying to solve this issue myself for quiet some time now.
but i fail to find any solution for it.

we are running several Asterisk´s (1.4.1) and i dont have the problem on the other servers.

– Got SIP response 486 “Busy Here” back from

[Dec 10 16:57:17] WARNING[17031]: chan_sip.c:12294 handle_response: Remote host can’t match request CANCEL to call ‘71e93bf64572cf033481544a05418ecd@’. Giving up.

the Asterisk wants to send a Cancel on a 486 response.

have anyone else encountered this behaviour before?
ive searched through the code for any hints to what can be wrong.