I aborted tonight's du after seeing this:
Retrieving bug reports... Done
Parsing Found/Fixed information... Done
serious bugs of mdadm (3.3.2-2 -> 3.3.2-3) <Outstanding>
b1 - #771852 - package not installable due to postinst syntax error
Summary:
mdadm(1 bug)
Are you sure you want to install/upgrade the above packages? [Y/n/?/...]
Seems there are bug reports already, and a patch, so, it might be worth waiting a bit.