Comment # 3 on bug 903051 from Wolfgang Bauer

(In reply to Neil F Brown from comment #1)
> A fix has been committed to Base:System:mdadm and submitted for inclusion in
> openSUSE.

This bug is still present in 13.2 final.
I got the same email yesterday:
Subject: Cron <root@amiga> source /etc/sysconfig/mdadm; [ -n
"$MDADM_CHECK_DURATION" -a -x /usr/share/mdadm/mdcheck ] &&
/usr/share/mdadm/mdcheck --continue --duration "$MDADM_CHECK_DURATION"
...
X-Cron-Env: <USER=root>
Message-Id: <20141111000007.B7B17A02CF2@amiga.site>
Date: Tue, 11 Nov 2014 01:00:03 +0100 (CET)

ls: cannot access /dev/md?*: No such file or directory

Apparently the fix didn't make it into 13.2:
# rpm -q --changelog mdadm|head
* Mon Sep 29 2014 nfbrown@suse.com
- cron.d.mdadm: add correct PATH setting
  (bnc#898239)

* Die Sep 16 2014 nfbrown@suse.com
- Add cron job to run 'mdcheck' regularly to
  verify all md arrays. (bnc#869261)

* Fre Jul 25 2014 p.drouand@gmail.com
- Remove insserv dependency; the package has been moved to systemd

That's with the one from the 13.2 repo:
# rpm -q mdadm
mdadm-3.3.1-5.3.1.x86_64

Would be nice to get the fix as online update...