Sort Posts by Rating (Backend)

I noticed recently that while logged in as Admin in the “All Posts” area of the backend, when I click on the “Rating” column to sort posts by columns the order does not appear to be correct (in both asc and desc). I’ve tried disabling all plugins other than WP Post Ratings, as well as reverting to the default theme with no luck.

Any ideas what could be happening?

Thanks,
Shane.

https://wordpress.org/plugins/wp-postratings/