Microsoft Teams Bot Crash when using ImageSet - botframework

Question

We had previously a Microsoft Bot using C# and adaptive cards. We have some templates stored. Suddenly Microsoft Teams starts to freeze and crash whenever a button is clicked on an adaptive card.
After some investigation, I found that the ImageSet in the adaptive card is causing the crash. By removing it, everything works fine, and when adding it, it crashes again.
Here's a preview of the adaptive card I'm using:
{
"type": "AdaptiveCard",
"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
"version": "1.4",
"body": [
{
"type": "ColumnSet",
"wrap": true,
"columns": [
{
"type": "Column",
"width": "auto",
"wrap": true,
"items": [
{
"type": "TextBlock",
"text": "Text",
"weight": "Bolder",
"size": "Medium",
"color": "Accent",
"wrap": true
},
{
"type": "TextBlock",
"text": "Random Text",
"weight": "Bolder",
"color": "Default",
"wrap": true
},
{
"type": "ColumnSet",
"$data": "${modules}",
"width": "stretch",
"columns": [
{
"type": "Column",
"width": "auto",
"items": [
{
"type": "ImageSet",
"images": [
{
"type": "Image",
"size": "Medium",
"url": "${ModuleImage}"
}
]
}
]
},
{
"type": "Column",
"width": "stretch",
"items": [
{
"type": "FactSet",
"facts": [
{
"type": "TextBlock",
"text": "**${ModuleTitle}**",
"value": "**${ModuleTitle}**",
"wrap": true
},
{
"type": "TextBlock",
"text": "${ModuleDescription}",
"value": "${ModuleDescription}",
"wrap": true
},
{
"type": "TextBlock",
"text": "${ModuleDuration}",
"value": "${ModuleDuration}",
"wrap": true
}
]
}
]
}
]
}
],
"verticalContentAlignment": "Center"
}
]
}
],
"actions": [
{
"type": "Action.OpenUrl",
"title": "Go To Google",
"url": "https://www.google.com"
},
{
"type": "Action.Submit",
"title": "Click me for messageBack",
"data": {
"msteams": {
"type": "messageBack",
"displayText": "I want to schedule a date.",
"text": "text to bots",
"value": "{\"buttonValue\": \"ScheduleDate\"}"
}
}
}
]
}
So what's wrong with this template? Is it a bug or what?