Installation failed with exception: Unexpected error while running command.

dpkg -l '*maas*'|cat
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===================================-==================================-============-===============================================================================
ii maas 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server all-in-one metapackage
ii maas-cli 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS command line API tool
ii maas-cluster-controller 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server cluster controller
ii maas-common 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server common files
ii maas-dhcp 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS DHCP server
ii maas-dns 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS DNS server
ii maas-proxy 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS Caching Proxy
ii maas-region-controller 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server complete region controller
ii maas-region-controller-min 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS Server minimum region controller
ii python-django-maas 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server Django web framework
ii python-maas-client 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS python API client
ii python-maas-provisioningserver 1.7.3+bzr3363-0ubuntu1~trusty1 all MAAS server provisioning libraries

I'm trying to install 14.04 onto UCS B-Series blade. I've done over a dozen blades w/o any issues. But this one particular blade is having problems and gives this in the install.log.

list index out of range
Installation failed with exception: Unexpected error while running command.
Command: ['curtin', 'block-meta', 'simple']
Exit code: 3
Reason: -
Stdout: 'list index out of range\n'
Stderr: ''

I grep'd on 'block-meta' and 'simple' in /etc/maas/preseeds and I can't find where this is being ran (I do have a custom curtin installer for another host -- but I moved it just in case, and no longer exists (it was doing something similar to the above block)).

It's not clear how to troubleshoot this, and/or how to enable more verbose logging to shed light on the cause of the problem.

Any insight would be greatly appreciated!