update-initramfs not finding UUID-less raid arrays in mdadm.conf

I found this in an unattended-upgrades notification email after a kernel upgrade:

update-initramfs: Generating /boot/initrd.img-3.13.0-24-generic
W: mdadm: the array /dev/md1 with UUID 69643aeb:2c2b10a0:1f51fb89:78ee93fe
W: mdadm: is currently active, but it is not listed in mdadm.conf. if
W: mdadm: it is needed for boot, then YOUR SYSTEM IS NOW UNBOOTABLE!
W: mdadm: please inspect the output of /usr/share/mdadm/mkconf, compare
W: mdadm: it to /etc/mdadm/mdadm.conf, and make the necessary changes.
W: mdadm: the array /dev/md3 with UUID 5254924c:1190c837:1f51fb89:78ee93fe
W: mdadm: is currently active, but it is not listed in mdadm.conf. if
W: mdadm: it is needed for boot, then YOUR SYSTEM IS NOW UNBOOTABLE!
W: mdadm: please inspect the output of /usr/share/mdadm/mkconf, compare
W: mdadm: it to /etc/mdadm/mdadm.conf, and make the necessary changes.

The messages are reproducable by running update-initramfs -u

/etc/mdadm/mdadm.conf contains raid arrays defined without UUID, as configured by server provider on setup:

# This file was auto-generated on Tue, 04 Mar 2014 11:35:34 +0100
# by mkconf $Id$
ARRAY /dev/md1 level=raid1 num-devices=2 devices=/dev/sda1,/dev/sdb1
ARRAY /dev/md3 level=raid1 num-devices=2 devices=/dev/sda3,/dev/sdb3

/usr/share/mdadm/mkconf returns raid arrays with UUID:

# definitions of existing MD arrays
ARRAY /dev/md1 UUID=69643aeb:2c2b10a0:1f51fb89:78ee93fe
ARRAY /dev/md3 UUID=5254924c:1190c837:1f51fb89:78ee93fe

Reboot worked fine with no changes to mdadm.conf

Replacing mdadm.conf with output of mkconf or adding UUID parameter after the others stops the warning.

mdadm version is 3.2.5-5ubuntu4

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: initramfs-tools 0.103ubuntu4
ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
Date: Wed May 7 08:58:01 2014
PackageArchitecture: all
SourcePackage: initramfs-tools
UpgradeStatus: No upgrade log present (probably fresh install)