> The strange thing is that my little program which simulates this
> behaviour works fine with sb and wss as well. (see the program at the
> end).
> 
> Any ideas what potentially could be causing this wierd thing?
Have you run ktrace?  It should show you exactly what is
happening so you can reproduce it.  If you find a small program
that tickles the bug, I'll try and fix it.

     -- Lennart