how to solve undefined event for dialogflow cx

Question

i'm able to catch event.detail.response.responseId and event.detail.response.queryResult.languageCode from Dialogflow Api in javascript (in function for df-response-received event).

But event.detail.response.queryResult.intent.displayName is undefined. Same thing for intent.name

What could be the reason why Dialogflow api returns undefined values ?

thanks Regards

i expected to retrieve the intent name.