Hi Chris,
Welcome to BuddyDev Forums.

Please open a new topic with it or if you need custom job, please contact via our contact form.

It is not a bug in the plugin as Activity comment notifier simply notifies of an activity comment and the following action are not handled by it:-

– When a user is added to a group
– When a group that user belongs to starts a new forum topic
– When their is a reply to a topic
– When there is an update of any sort to a group

You are right about the Group Email subscription.

I am not sure if there exists any plugin that covers all of it and it will most probably need custom coding.

Thank you
Brajesh