Posting here as Steam Support Requested.

My Steam Friends Chat is broken. Any Youtube video links only display as a black box now.

1. Tried to clear browser cache
2. Tried hardware acceleration on/off
3. Tried turning Millennium theme on/off
4. Tried reinstalling Steam Client

The problem still exists. Verified with update that I had latest client.

As you can tell that it seems the embed of videos is not working in Friends Chat. If I turn off embed than I can at least see the URL they are sending me.

Files attached: Screenshot_1.jpg