$ curl -s -k -u jenkins:pass -H Content-Type:application/json -H Accept:version=2,application/json -X PUT -d '{"build":false}' https://foreman.example.lab/api/hosts/fna060.be.example.lab                                                                                                      
{
  "error": {"id":435,"errors":{"base":["Failed to generate PXELinux template: undefined method `encoding' for nil:NilClass"]},"full_messages":["Failed to generate PXELinux template: undefined method `encoding' for nil:NilClass"]}
}

• jenkins is a non admin user
• '{"build":true}' works to put the host in build mode
• At the end the host is still in build mode
• It is broken in the webui as well