Rules for create_operatingsystems not effective after update

Problem:
A regular (non-admin) foreman user is not allowed to create an operating system, even if all rules are assigned to that user. The Error “You don’t have permission create_operatingsystems with attributes that you have specified or you don’t have access to specified Organisationen” occurs when one wants to submit a new operatingsystem. This error does not occur with the admin-user.
Version
With foreman-Version 1.14 we had no such issues. After upgrading via 1.15 to now 1.16.1 the error occured. We had a similar issue that was repaired by applying the changes discussed in https://github.com/theforeman/foreman/pull/5470/files
Other relevant data:

2018-07-23 11:45:33 e52f321c [app] [I] Current user: ymuster (regular user)
2018-07-23 11:45:33 e52f321c [app] [I] Completed 200 OK in 11ms (Views: 0.1ms | ActiveRecord: 1.1ms)
2018-07-23 11:45:37 ade10c65 [app] [I] Started POST “/operatingsystems” for .***.***. at 2018-07-23 11:45:37 +0200
2018-07-23 11:45:37 ade10c65 [app] [I] Processing by OperatingsystemsController#create as /
2018-07-23 11:45:37 ade10c65 [app] [I] Parameters: {“utf8”=>“✓”, “authenticity_token”=>“some/tokens==”, “operatingsystem”=>{“name”=>“Ubuntu”, “major”=>“18”, “minor”=>“04”, “description”=>“Ubuntu_18_test”, “family”=>"", “release_name”=>"", “password_hash”=>"[FILTERED]", “architecture_ids”=>["", “3”], “ptable_ids”=>[""], “medium_ids”=>[""]}, “_ie_support”=>""}
2018-07-23 11:45:37 ade10c65 [app] [I] Current user: ymuster (regular user)
2018-07-23 11:45:37 ade10c65 [app] [I] Failed to save: You don’t have permission create_operatingsystems with attributes that you have specified or you don’t have access to specified Organisationen
2018-07-23 11:45:37 ade10c65 [app] [I] Rendered operatingsystems/_template_defaults.html.erb (0.3ms)
2018-07-23 11:45:37 ade10c65 [app] [I] Rendered common_parameters/_parameter.html.erb (5.9ms)
2018-07-23 11:45:37 ade10c65 [app] [I] Rendered common_parameters/_parameters.html.erb (13.8ms)
2018-07-23 11:45:37 ade10c65 [app] [I] Rendered operatingsystems/_form.html.erb (75.5ms)
2018-07-23 11:45:37 ade10c65 [app] [I] Rendered operatingsystems/new.html.erb (76.0ms)