So this is an interesting "quirk." Not necessarily a bug with the top posters plus app as it does not touch meta tags, etc... itself. This "page" is actually not even a real page necessarily. This "quirk" is related to how the IPS core software handles meta tags with the meta tag editor. If you have assigned tags using the meta tag editor to the "/" URL then this will happen as we use query strings in the URL to use this ajax call and not a distinct FURL.
Little technical background, "/" = "/index.php" therefore the IPS core software is saying "Hey, they want these meta tags here too" and places them on the URLs you listed.
To fix this, you can apply the following furl.json file to /applications/jimmotoppostersplus/data/ . This will assign a custom FURL to this page and you won't see any meta tags you've assigned to "/" on the page anymore. If you have any issues, make sure you clear your cache.
(in the future, we'll see if we can't add a "noindex" tag to this "page" as well as there shouldn't be any worthwhile index-worthy data there.)