Resolved
Resolved in: Forms 2.6.7
When a form to publish posts is rendered on the front-end a provisional post (titled CRED Auto Draft, with status of auto-draft) is created in wp_posts, which eventually gets converted to the actual post once the form has been submitted.
If the form is never submitted, orphan auto-draft posts are left in wp_posts, but there is a routine job to clean up these left-over draft posts.
This currently isn’t working, meaning that such auto-draft posts can accumulate in the database.