Title overwrite in contextual filter does only print user id instead of user name

Hi @ all,

I created views like described here (https://drupal.stackexchange.com/questions/268726/view-flag-and-followers/268735#268735) and everything works fine aside one thing:

when I use the user ID of the flagging user as contextual filter, and overwrite the views title with e.g. {{ arguments.uid }} follows I get only the user ID printed out instead of user name: 1 follows instead of Superman follows

When I use user ID of User Category as the contextual filter and do a title overwrite like {{ arguments.uid }} following it's printing the username as expected in my view.