If you access the profile of any user and they’re in-game, you’re able to see what game they are playing—even if their joins/game visibility is turned off.
I assume this is a bug, because if you have the user added and their game visibility is set to “No one,” you cannot see their game. However, if you switch to an account that doesn’t have them added, you are able to click the green dot or hover over it to see what game they’re currently in.
If you attempt to join them, it will give the error that the ‘followed user has left the experience’.
Expected behavior
The visibility of a user’s game must be in accordance to the users privacy setting.