Date recorded field won’t take a date

I am having a problem assigning a “date recorded” to a podcast episode.

First, I am confused that there are two places for it: (1) the box headed “Date Recorded” in the “Podcast Episode Details” frame immediately under the description, and (2) an entry for the field “date_recorded” in the “Custom Fields” frame lower down the page. Which should we use? Does it matter?

More important, I can’t get the “date recorded” to stick. I am using the format YYYY-MM-DD, which is the most logical format. When I insert a date in this format in the “date_recorded” custom field and click update below, the field flashes yellow and the date is visible. If I then click “update” under the “Publish” box, the date doesn’t carry through.

What is going on? How can I get the date published to stick? Which of the two fields should I use, and what format should the date be in?

Thanks!