I tapped on one of them and I got error after error not being able to resolve the url or something, it was very fast and I couldn't read the message. I had to restart the phone because I was unable to close the app, it kept bringing it back on even after putting the phone in airplane mode.
I guessed the same, that it had to be a deleted user. It was rather funny at first, after a minute I realised it was impossible to stop.