I was not able to reproduce this, however I was using 1.4.36 for my test. We'd need a complete debug [1] log reproducing the issue, plus a copy of your sip.conf (be sure to mask any passwords).
[1] https://wiki.asterisk.org/wiki/display/AST/Collecting+Debug+Information -- Paul Belanger | dCAP Polybeacon | Consultant Jabber: paul.belan...@polybeacon.com | IRC: pabelanger (Freenode) | Blog: http://blog.polybeacon.com | Twitter: http://twitter.com/pabelanger -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org