Comment 7 for bug 1005575

Well, it didn't take long to find others with this same issue. :) I installed Mint 13 Cinnamon 3 or 4 nights ago, but I think this behavior of the clock seizing didn't show up until tonight-- I think I would have noticed it previously. In my case the clock updates to the correct time at 8 minutes past each hour and then doesn't advance any further until another hour has passed and it sets itself correct again.

My format strings are
panel: %a %b %e %l:%m %p
inside date applet: %A %B %e, %Y