yep, I can confirm this settings istn't working (anymore!?). tbh - I added this in the very beginning when I wasn't sure if the grouping works fine and it might be preferrable to be able to prevent certain movies from being grouped together - but I never used the option myself, as the plugin does what I want in the background without worrying about it 😉 So ... I would suggest removing the setting to get rid of the issue - unless there are really good arguments why it is needed !?