Recently I got added to a studio, and when I got on the forums it showed this notice:

You are only supposed to see messages in, well, your messages inbox, and this is randomly on the top of the forums. This also disappeared when I accidentally clicked Suggestions when I was trying to make this topic. Has anyone else seen this notice, and why is it here in the forums?

It was meant to display that you got added as a curator, but it broke when the studio update released due to it changing how it worked and not using the notices thing anymore. If you do something like reply or edit you might notice what it was meant to do.
Edit: My brain is failing to work so I had to edit this lol

This happened to me before. Its just a bug.