In the Virtual Service Image with a transaction that contains a JSON response, select Tree View and then set it back to Text View.
The JSON response will have escape characters that were added automatically.
Below images show how to reproduce this behavior:
In the image we can see the response does not contain the escape character:
Change the view from Text View to Tree View:
The Tree View:
Change the View back to Text View:
Notice the escape characters were added to the response: