When I edit a file in the CMS, the "File uploaded" value is always reset to a date 38 years ago. On my laptop (which has a local time zone west of GMT) it's the 31/12/1969, on my web server (located in a time zone east of GMT) it's the 01/01/1970. These are not only display differences, but appear this way in the respective database.
To reproduce this, it's enough to open the "Edit" dialog, then to click on "Save" in the "Main" tab.
Silverstripe version: 2.2.2rc3
It's reported as a bug and currently in the list for the 2.2.3 milestone. Unfortunately I couldn't really find a fix for it, my current workaround is running the following query in the database after I changed anything with the file edit dialog:
UPDATE `File`SET `Created` = `LastEdited` WHERE `Created` < '1980-01-01 00:00:00';
It doesn't really fix the issue, but at least I get a date that makes more sense than the one 38 years ago.
I fixed that error on my installation about 1 month ago, and also reported the fix at [url]http://open.silverstripe.com/ticket/2495#comment:2[/url]. Unfortunately, it will still take quite a while until this will appear in any Silverstripe release.