Widget MediaPlayer view cut off & Adaptive Card Media poster not working

Describe the bug

Environment
OS: Windows 11
Build: 25H2 (26220.7535)
Widgets Platform: Windows Widgets (Adaptive Cards 1.6)
Card Version: Adaptive Cards v1.6

The MediaPlayer view inside the widget appears cut off on the right side. The media player controls lose their rounded corners, and the layout looks clipped instead of properly contained.

Additionally, the Media post in the widget does not work at all — the video content does not behave/render correctly even when valid URLs are supplied.

Expected behavior
Media player should respect rounded corners on all sides.
The Media element should render correctly inside the widget.

Actual behavior
Right side of the MediaPlayer appears clipped.
Rounded corners are missing on the player controls.

Media content does not function as expected inside the widget.

Steps to reproduce the bug

Code i use for poster:
{ "$schema": "http://adaptivecards.io/schemas/adaptive-card.json", "type": "AdaptiveCard", "version": "1.6", "fallbackText": "Play", "body": [ { "type": "Container", "items": [ { "type": "Media", "poster": "${ThumbnailUrl}", "sources": [ { "mimeType": "video/mp4", "url": "${VideoUrl}" } ] } ] } ] }

I try base64 or just URL for variable ThumbnailUrl.

Expected behavior

No response

Screenshots

NuGet package version

None

Packaging type

No response

Windows version

No response

IDE

No response

Additional context

No response

Begin by reproducing the supplied Adaptive Card in Windows Widgets on Windows 11 with Adaptive Cards 1.6, testing both the MediaPlayer clipping and poster/video behavior. Trace the Media element rendering path; done means the player is fully contained with rounded corners and valid poster and video URLs render correctly.