Custom Field Created by User in Listing not Parsing to WordPress Admin

Guys, I need help. I made a custom field for listings with a key ‘youtube’. The purpose of the field is that users can put a url for their youtube video to show up on the listing. Now, when user submits the listing to admin for approval everything still looks OK on the front end at the pending listing page, and the user can see youtube video. However, when admin goes to a pending listing to approve it, the custom field is blank, and it doesn’t contain youtube link. Therefore, when admin approves the listing, youtube link is non existent, and youtube video doesn’t show on the listing page.

What could cause this problem?

Thanks!