I've just noticed that our hidden categories have a different "visited" colour. Initially, hidden categories are grey, but then change to our theme's link colour. I wouldn't think that the categories would use a visited colour. I've removed all of our custom CSS to see if the problem was there, but it made no difference.
Is this normal? Is this happening to others? I don't want to spend any more time on it if it's by design, but if it's unique to our situation then I will continue to try to figure it out. We are using Essential version 2014090307.