LocalisationUpdate process had been broken for some time for extension messages. It probably broke while doing an "SVN update" on November 19th. This has now been fixed.
Since the last update of the MediaWiki software on all projects, 24090 localised messages have been added. You can find a breakdown per language here.
In order to be sure that we have all the possible messages available from LocalisationUpdate, Roan has triggered a full upgrade for all the message files. This was done by removing the "hash values" for the message files.