Posts keep reverting to draft status

I have recently set up a site that is a directory of Australian golf courses. I have entered all of my posts (courses) into a CSV file and uploaded into the database.
All works fine and is showing the courses correctly except for 19 of them (out of 1520) keep reverting back to draft status. I have tried deleting them completely and adding them back to the database but they always end up going back to draft status. They all have the same post type, post date, post status etc.
I have deleted their revisions and have now turned revisions off. Is there something I could be missing?

Thanks