Templates language is not supported in Teams

[karolyxy]

I have tried to use template language in my adaptive cards posted in Teams chat. However, my $data is simply being ignored and cannot be launched. I basically follow the expense report sample. The following is my adaptive card.
{ "type": "AdaptiveCard", "body": [ { "type": "TextBlock", "size": "Large", "weight": "Bolder", "text": "Please confirm all your projects below" }, { "type": "TextBlock", "wrap": true, "text": "All info below are based on the records you have handed into the online New Project Setup Form and Network Access Request Form. If nothing shows up, please click \"More to submit\" button to transfer all your ongoing projects to the desired users.", "spacing": "Small" }, { "type": "Container", "items": [ { "type": "ColumnSet", "columns": [ { "type": "Column", "width": "stretch", "items": [ { "type": "TextBlock", "text": "Project Folder Path", "wrap": true, "weight": "Bolder" } ] } ] } ], "bleed": true, "style": "emphasis" }, { "type": "Container", "items": [ { "type": "ColumnSet", "$data":"${AllAttendedProjects}", "columns": [ { "type": "Column", "width": "stretch", "items": [ { "type": "TextBlock", "wrap": true, "id": "projectPaths", "text": "${PPath}" } ], "id": "ProjectFolderPath" }, { "type": "Column", "width": "auto", "items": [ { "type": "Image", "url": "https://adaptivecards.io/content/down.png", "width": "20px", "id": "chevronDown${$index}" }, { "type": "Image", "spacing": "None", "isVisible": false, "url": "https://adaptivecards.io/content/up.png", "width": "20px", "id": "chevronUp${$index}" } ], "spacing": "None", "selectAction": { "type": "Action.ToggleVisibility", "title": "expand", "targetElements": [ "cardContent${$index}", "chevronDown${$index}", "chevronUp${$index}" ] } } ] }, { "type": "Container", "items": [ { "type": "TextBlock", "text": "Enter the email address who will continue on your this project", "wrap": true, "size": "Small", "weight": "Lighter" }, { "type": "Input.Text", "placeholder": "e.g. xxx.xxx@tigermedgrp.com", "id": "ProjectRecipient" } ], "isVisible": false, "id": "cardContent${$index}" } ] }, { "type": "ActionSet", "actions": [ { "type": "Action.OpenUrl", "title": "More to submit", "url": "https://macrostat365.sharepoint.com/sites/tgbm-all-IT/Lists/Work%20Transition%20Form/AllItems.aspx" }, { "type": "Action.Submit", "title": "Confirm" } ] } ], "$schema": "http://adaptivecards.io/schemas/adaptive-card.json", "version": "1.2" }

Here are my sample data:
{ "AllAttendeProjects":[ { "PPath": "\\\\mst13\\Training" }, { "PPath": "\\\\mst13\\Timesheet" }] }