That's funny. I saw that today and thought Groups were broken since I was so used to seeing the Groups with the most recent post be at the top. Instead, (just like your image) there was hours of time separating the top group from the one with the most recent post.
I think Groups are hard for new members to figure out. What's a group? Am I posting a discussion? Am I posting a question? If I'm posting a question, why am I not using the Question section? What group(s) do I join? What groups exist? Why can't I search Group content?
I guess it makes sense to feature and promote GrabCAD groups. But, the Community User Group is already the default group where many new members post unrelated content. Having that Group permanently at the top is likely going to increase those weird posts.
