diff --git a/lib/kubeclient.rb b/lib/kubeclient.rb
index c82420ea..6e49d765 100644
--- a/lib/kubeclient.rb
+++ b/lib/kubeclient.rb
@@ -497,7 +497,7 @@ def apply_entity(resource_name, resource, field_manager:, force: true)
       response = handle_exception do
         faraday_client.patch(
           "#{ns_prefix}#{resource_name}/#{name}",
-          resource.to_json,
+          resource.to_h.to_json,
           { 'Content-Type' => 'application/apply-patch+yaml' }.merge(@headers)
         )
       end