Last modified: 2013-10-26 15:15:43 UTC
When there is no creation date found by CommonsMetaData and we fall back to file upload date, it is shown in a raw format (e.g. 2013-10-24T19:53:46Z).
Somewhat fixed in https://gerrit.wikimedia.org/r/#/c/91874/ Shows date string in browser language - not ideal, but better than an ISO string.
FWIW we're considering fixing this by adding a new core module that would do more and cooler formatting stuff, based on http://momentjs.com
Done-ish for now - the Date() approach is a little nasty but we've at least stopped it from including HTML.