At for example the tag amsterdam I can hover over the tag name itself in the right corner and a small pop-up will appear showing the amount of followers and a short description of the tag:
If I click the star, I favorite the tag, and the number of followers increases by one. This works as it should be:
However, if I click subscribe after that as well, the number of followers increases again, making me a duplicate follower:
Is this by design or is this a bug?