Quoting Jesse Molina <jesse@opendreams.net>:
I had this same problem a week or two ago and had to downgrade. Two separate systems with very similar configs both showed this behavior. A few messages were logged, then after fifteen minutes or less, no more output. The process was running but nobody was home.
I regret that I didn't bug it, but I just don't have time on the side to deal with it right now.
The system is Debian GNU/Linux, Unstable, on i386.
same for me Debian unstable I can't risc to put back the 1.9.9 version I can just hope it is reproduceable on my testserver which has been upgraded today. I only have a strace of mailq which then hangs while trying to access /dev/log want me to send this? else if the error occours on the testserver I can do watever trace or test you need.