Dates out of whack on blog posts

I just launched a new blog called https://www.magiccitymania.com using the Henge 1.0 theme.

For some reason, the dates that get posted with each blog post are completely out of whack.

The date on the first blog post is Monday
0/28/2008 even though the actual date listed in my admin page is 2008/04/28

The date on the second blog post is Tuesday
8/29/2008 even though the actual date listed in my admin page is 2008/04/29

And the date of the third blog post is Wednesday
23/07/2008 even though the actual date listed in my admin page is “5 hours ago”.

The date format in my settings page is accurate.

How can I fix this issue?