I saw a notice in my Achievements suggesting that I was removed as a user from the Bricks group. As far as I can tell this isn’t true, but I’m still wondering what to make of the notification. Can anyone shed light on why i received the notification or what it means? See screenshot.
It means that another user that voted on one of your questions or answers was removed from the site. When this happens, the system reverts all the reputation changes that happened when that user upvotes or downvotes on posts.
There are a number of reasons that an account might be removed ranging from the user requesting it themselves, through to the account being linked to spamming or sock puppets.
For more details, please see this help topic: Why do I have a reputation change on my reputation page that says 'User was removed'?