[reSIProcate-users] Why the Dum(stack) send 488 respone for re-INVTE ?

[Karlsson <boost.regex@xxxxxxxxx>]

Hi all, when I received a call, my UA answered the 200 ok. 
But why when received the re-INVITE, the reSIProcate respone the 488 to remote side ?

The attachment it's stack log.

Thanks.

Attachment: log.log
Description: Binary data