Subscribe/unsubscribe from categories

There seems to be an issue with the subscribe/unsubscribe button for categories, both on this Community and on our own Community (so I guess it's a general issue):

• It says "Unsubscribe" on all categories, even though I didn't subscribe to them
• When I click the button, it changes to "Subscribe" but when refreshing or coming back to the page, it is on "Unsubscribe" again
• I don't think I receive emails on new topics in subscribed categories anymore