Users that i am not yet following, but ends up in my inbox through a share/like from one of the users i am following, often have the "stop following" button in their avatar dropdown menu.

Using the button returns a network error in the status bar (as you can't unfollow users you're not following)

Using Pumpa compiled from git commit 7352d2be5d2ac8a9f675813b00326a8032f2342f