Attach posts based on category and position

I’m wondering if you’re actually looking at post revisions. Keep in mind that WordPress creates a revision of a post any time you make a change to it. Each revision stays in the database, however, the way you access it is by going into the post itself and then locating the revision section in the upper right hand corner.

The posts you see might actually not be “orphaned” posts.

I would also recommend you consider doing some WordPress maintenance to clean out older post revisions. I would recommend you look into using WP-Optimize for this (be sure to read the documentation). See if that actually addresses your issue.