From the "start" section of /etc/rc.d/init.d/random action $"Initializing random number generator: " /bin/true chmod 600 $random_seed dd if=/dev/urandom of=$random_seed count=1 bs=512 2>/dev/null I could be mistaken, but it appears to me that the input and output of dd are the wrong way round for this to actually feed any entropy into the random number generator.
Closing this myself, as reporter. This is not a bug. I hadn't read the script carefully enough: it is a previous line that initialises the random generator ("cat /var/tmp/random-seed >/dev/urandom"). Sorry to take your time.