Last Linux/Mac l10n builds in http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-mozilla-central-l10n/ are created on May 27. Windows l10n builds are missing.
Can't spot anything useful in the logs, besides the really weird names http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2015-05-30-03-02-05-mozilla-central-l10n/
I wonder if this is fall-out from bug 740142, aka, using mozharness for repacks on desktop. Moving to buildduty, that might be better suited.