[Designer] Designer not displaying input values on submit

[RebeccaAnne]

Problem Description

When choosing a submit action in preview mode, the values of the inputs are not shown in the popup.
(This repros on the deployed designer version)

Card JSON

{
    "type": "AdaptiveCard",
    "version": "1.3",
    "body": [
        {
            "type": "Input.Text",
            "label": "Type something:"
        }
    ],
    "actions": [
        {
            "type": "Action.Submit",
            "title": "Submit",
            "data": "Here's some data"
        }
    ]
}

Screenshot

The popup that comes up when you press submit does not include the value of the input (it does include the submit data):

Card: