Collection is not working or loading correctly.
If a collection does not load correctly, it may be because a piece of content is in a checked out status.
Use the following query to list the content that is part of the collection. Update the nav_id value to be the collection ID (available in the collection properties).
SELECT content_id,content_status,content_type,end_date,* FROM content WHERE content_id in (select content_id from nav_to_content_tbl WHERE nav_id = 4 AND content_language = 1033)
Once you determine which content items are checked out and either check in or publish them, the collection should load as expected.