I have it on good authority that the LocalisationUpdate script can sometimes incorrectly/inaccurately report success (e.g., outputting "!log LocalisationUpdate completed (1.22wmf1) at Wed Apr 17 02:10:22 UTC 2013" to the server admin log) when in reality the localisation update did not run successfully.
The error-checking or reporting logic needs a review. Filing this as a bug so that this issue doesn't get lost.
Version: unspecified
Severity: normal