The API v1 hosts views use the puppet_status attribute, which is a deprecated getter from #10782, where only the v2 API was fixed to use the new version.

test/functional/api/v1/hosts_controller_test.rb prints:

DEPRECATION WARNING: You are using a deprecated behavior, it will be removed in version 1.13, Host#puppet_status has been deprecated, you should use configuration_status. (called from app_views_api_v_hosts_create_json_rabl__1200163205771380870_129174860 at /home/dcleal/code/foreman/foreman/app/views/api/v1/hosts/create.json.rabl:3)