The iTunes team is aware of delays with the iTunes store updating with new and changed content. If new content is released on your RSS feed, the iTunes store may not update within the typical 24 hour time frame.
Subscribers still are able to access your content. This only affects the iTunes store.
If you find your show as not updating properly, first make sure your feed is in good working order. Follow the steps found here.
If your feed is in good working order, please contact the iTunes team directly at firstname.lastname@example.org. Make sure to provide the URL to your show in the iTunes store and note that you are missing an episode. They have requested producers contact them directly as their team can force through changes and updates. It also allows them to track the issue so their engineers can locate and correct the problem.
Feel free to reach out to our support staff with any questions at email@example.com.