Upgrade to Lucid improperly modifies mdadm.conf

Binary package hint: mdadm

System has an IDE boot drive as /dev/hda and a software RAID of four SATA drives as /dev/hdb, /dev/hdc, /dev/hdd, /dev/hde.
On upgrade from Karmic to Lucid, the /etc/mdadm/mdadm.conf file had the following change automatically made:

# definitions of existing MD arrays

#ARRAY /dev/md0 devices=/dev/sdb1,/dev/sdc1,/dev/sdd1,/dev/sde1
ARRAY /dev/md0 devices=/dev/sda1,/dev/sdb1,/dev/sdc1,/dev/sdd1

This caused two inactive arrays to get created at the next boot _after_ an apparently successful upgrade, one with sdb1, sdc1 and sdd1, and another with only sde1. My presumption is that somehow during the upgrade, some disc scan is putting the SATA drives ahead of the IDE drive, so the scan thinks the array definition in /etc/mdadm/mdadm.conf is incorrect, and replaces it with one which won't work at next boot.