It was happening with the base sshd, which was recompiled during the buildworld. As soon as I disabled sshd monitoring in the services.status file the problem was fixed. As I said this is my experience on one box I didnt say it will happen to everyone.
--edit--
I am not blaming an operating system for it, ssh on v6 is stable, but something is triggering DA to run the sshd restart script after we upgraded to 6.0 I hope that makes it clear what I was saying now.