Board Thread:Support Requests - Getting Technical/@comment-38546635-20200715015707/@comment-26611127-20200715021654

Your wiki utilizes Fandom's new UCP platform (Help:UCP), which doesn't support the activity feed tag.

On legacy wikis, the tag derives information from WikiActivity, which is currently not a feature on UCP.

You can to ask them for more information in regards to the aforementioned features, but as far as I know there hasn't been any clear answer on when or if these features will return.