CKAN version: API 3

Describe the bug

When I make an API call to group_list and try to sort them by count it shows a wrong order.

Steps to reproduce

https://mobidata-bw.de/api/action/group_list?all_fields=true&sort=package_count
https://mobidata-bw.de/api/action/group_list?all_fields=true&sort=package_count%20asc
https://mobidata-bw.de/api/action/group_list?all_fields=true&sort=package_count%20desc

All of them show the wrong order/sort.

Expected behavior

I expect the sort=package_count to show a correct sorted list.

Additional details

When I open the list in ckan directly everything is fine: (see sidebar)
https://mobidata-bw.de/dataset

The same problem occurs with "organization_list":
https://mobidata-bw.de/api/action/organization_list?all_fields=true&sort=package_count%20desc

The deprecated"order_by" does not work too:
https://mobidata-bw.de/api/action/organization_list?all_fields=true&order_by=packages