Rated 5 out of 5 stars

Thanks for the fix. The "Hide" function seems to be working correctly now.

Rated 2 out of 5 stars

This was a great add-on several years ago, but since YouTube now has a native grid layout as default for the subscriptions page, YSG has become unnecessary. Also, hiding watched videos no longer functions correctly. It hid all my unwatched videos, and the watched ones were still displayed.

This review is for a previous version of the add-on (1.18.1). 

This is true, YT did revert back to a grid functionality making the extension less useful, although it does provide some added functionality still that people find worth while.

In addition YT in the last day made a change that only shows the most recent 10 videos uploaded per day by default - in the next version of the extension - which is in review now and should be live shortly - this is "fixed". This new version also fixes the bug you mention :)