Noticed something strange when viewing a twitter page on the iPhone mobile view. There was a blue oval-looking button on the screen:

When I clicked on it, I was shown a dialogue window asking me if I wanted to unfollow the account I was viewing. This was completely unexpected. As can be seen in the image above and the image below, I’m not signed into Twitter. So how can I unfollow someone, if I’m not even signed into an account?!?

On click of Unfollow, the Sign in screen is presented to the user.

The correct user behavior would be to not show a button to unfollow if the user is not signed in. If anything, the user should see a Follow button that should activate Sign in on click if the user is not signed in.