If there is only one organization or location, it's automatically filled it when creating new host and causes this error. 

NoMethodError (undefined method `to_a' for "75":String):
  app/controllers/hosts_controller.rb:492:in `taxonomy_scope'
  lib/foreman/controller/host_details.rb:42:in `assign_parameter'
  lib/foreman/controller/host_details.rb:7:in `architecture_selected'
  lib/foreman/thread_session.rb:31:in `clear_thread'