The invalid content has most likely long been deleted from the web service if you reported it, but when we mods delete an item from the web service it essentially becomes hidden on the web service, but it is not removed for you locally if you already have it so you won't see a change. The intention of that was I believe to stop users that had invalid content suddenly seeing large chunks of their collection disappearing but it means currently that you may have to fully remove the series from your collection, and that means all references so if a series is for example mapped to multiple disc titles in your collection, you need to remove them all. If you close then re-open Collection Management you should get a pop up that a series has been removed which would indicate it has been fully removed, then you can re-add everything. Note if you have your episodes as files and you already have any of the invalid content pointed at those files such that xmls have been created for them that point to the deleted (hidden) invalid content, I think you will need to delete those xmls as well or monitoring or import will if used re-add the deleted invalid content those xmls point to again I believe. That should ensure any of that old deleted invalid content is wiped from your collection locally.