[Rendering] Power Automate's "Get an @mention token for a user" action generates the correct <at>...</at> but the Workflows bot is no longer able to render user @mentions

Target Platforms

Other

SDK Version

1.5

Application Name

Microsoft Teams

Problem Description

This action in Power Automate would generate a HTML-like tag to the effect of <at>user-id</at> :

Cards posted by the Workflows app used to be able to render this correctly, but now it can only be rendered properly by cards posted as a user:

Screenshots

Card JSON

{
    "$schema": "https://adaptivecards.io/schemas/adaptive-card.json",
    "type": "AdaptiveCard",
    "version": "1.5",
    "msteams": {
        "width": "full"
    },
    "body": [
        {
            "type": "TextBlock",
            "text": "Dear Executive Staff, please be aware of the following meeting that has been scheduled. A calendar entry has also been created within the mailboxes of those notified.",
            "wrap": true,
            "color": "Accent",
            "size": "Small"
        },
        {
            "type": "TextBlock",
            "text": "Staff notified: @{outputs('Get_an_@mention_token_for_a_user')?['body/atMention']}",
            "wrap": true,
            "size": "Small",
            "color": "Accent"
        }
    ],
    "msTeams": {
        "width": "full"
    }
}

Sample Code Language

No response

Sample Code

No response

The issue identifies no repository file, test, or entry point. Start by reproducing the supplied Adaptive Card JSON through the Workflows bot and compare it with a card posted as a user; done means determining whether the regression is in this project and documenting or fixing the rendering behavior.