This is about the screens in the admin (backend) that list posts, pages, custom post types, etc.
The date in the "posted" column does not follow the date format preference setting. Nor does it seem easily possible to otherwise format it.
It should be possible to customize or even localize this date display.
After some extensive searching, I've not found this issue addressed anywhere, except a fix that was integrated into the wordpress core four years ago. (Ticket #2601) That fix doesn't seem to apply to the dates shown in the "posted" column.
Does anybody have experience setting the formatting of this date?