Getting conversation data with "Null" values..

Hello..

We are just going to launch our app in the Marketplace..
Before launching, we are testing the app functionalities by uploading the app build as a private app in a trial account..

During testing, we came across some difficulties..
We are using "client.on('ticket.conversation.changed')" property to get the latest conversations.. But unfortunately I'm getting empty conversations as like below.. All the conversation informations I'm getting as "null"..

Can you please give any suggestion for this?

Thanks..