Mentions (<at> Tags) Doesn't Work in Nested Elements Like TableCell in Adaptive Cards

I am creating a table in my Adaptive Card and want to tag people inside the cells. However, this doesn't seem to be possible. If I use the mention in a top-level TextBlock, it works though. Could you please help me with this issue?

My Adaptive Card looks like this:

card = {
    "type": "message",
    "attachments": [
        {
            "contentType": "application/vnd.microsoft.card.adaptive",
            "content": {
                "type": "AdaptiveCard",
                "version": "1.4",
                "width": "stretch",
                "body": [
                    {
                        "type": "TextBlock",
                        "text": "This is my table",
                    },
                    {
                        "type": "Table",
                        "columns": [
                            {
                                "type": "TableColumn",
                                "width": "stretch"
                            },
                            {
                                "type": "TableColumn",
                                "width": "stretch"
                            }
                        ],
                        "rows": [
                            {
                                "type": "TableRow",
                                "cells": [
                                    {
                                        "type": "TableCell",
                                        "items": [
                                            {
                                                "type": "TextBlock",
                                                "text": "",
                                            }
                                        ]
                                    },
                                    {
                                        "type": "TableCell",
                                        "items": [
                                            {
                                                "type": "TextBlock",
                                                "text": "Col 2",
                                            }
                                        ]
                                    }
                                ]
                            },
                            {
                                "type": "TableRow",
                                "cells": [
                                    {
                                        "type": "TableCell",
                                        "items": [
                                            {
                                                "type": "TextBlock",
                                                "text": "Row 1",
                                            }
                                        ]
                                    },
                                    {
                                        "type": "TableCell",
                                        "items": [
                                            {
                                                "type": "TextBlock",
                                                "text": "<at>Miles GOLD</at>",
                                            }
                                        ]
                                    }
                                ]
                            }
                        ]
                    }
                ],
                "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
                "msteams": { 
                    "width": "full",
                    "entities": [
                        {
                            "type": "mention",
                            "text": "<at>Miles GOLD</at>",
                            "mentioned": {
                                "id": "[email protected]",
                                "name": "Miles GOLD"
                            }
                        }
                    ]
                }
            }
        }
    ]
}