Feed is not updated after a week

Hey,

we have our site RSS updated, but the last item does not appear in iTunes.

Feed URL: http://feeds.feedburner.com/VenusIndex?format=xml

The last item:

Mountain climber, Amparo Used Venus to Sculpt Her Shape

Posted:Tue, 23 Jun 2015 05:45:18 +0000

is still not in iTunes, even though it was posted a week ago.

Anyone have an idea where the issue might be?

Thanks for your help