D8 deletes taxonomy on a node when updating alias or perfoming an action

I am deleting old users and before I do this I change the author of the nodes to user 1.
I made an action “change author to usernameAdmin(1)”. When I perform this action on nodes Drupal deletes the taxonomyterms of the nodes.
It´s doing this also when I perform an URL Alias update (delete and bulk generate).
Is this a bug? Am i doing something wrong?

And btw: is there a possibility to bulk-delete users or ANYTHING? When I hit the “check all” Box in an overview (users or nodes) it´s only taking the users /nodes on page 1. I mean… 16k users result in 320 pages….
I used the delete-all module but I am a bit afraid this is not the supposed way.



Drupal version: 

Source: https://www.drupal.org/taxonomy/term/22/feed