I was having all sorts of video playback & interface issues with version 184.108.40.2066. I performed a system restore this morning (turn off, wait 10 seconds, press power for 8 seconds), and this time it upgraded to 220.127.116.115 rather than 18.104.22.1686. Now playback is working fine on everything I've tried. There are still issues, but at least I can watch my content.
I tried several system restores yesterday with no luck. If you're still having problems, it might be worth trying it one more time today.