Playback Failure on Roku Ultra 4850X after an update

Since updating to Roku OS 15.0 build 4.5534-G6, I've encountered a recurring playback failure on my Roku Ultra 4850X that goes beyond app-specific glitches. In both the Disney+/Hulu hybrid app and Paramount+, I've documented that after selecting "Play" on a title, the screen goes completely blank and becomes unresponsive. The Home button fails to exit the session, and the only recovery method is a full power cycle.

This isn't an isolated app issue—I've documented this behavior across the Disney+/Hulu hybrid app and Paramount+, confirming it began immediately after the OS update. It's a system-level failure in playback registration and UI recovery. The device accepts the play command but fails to surface the stream, and worse, it locks out the interface entirely. That's not just a bug—it's a breakdown in platform responsiveness. 

There's no rollback option, and the previously available diagnostic shortcut ("HX5 UDUDU" speed test) is now disabled, removing a key tool for verifying system health in real time.

If other users are experiencing similar playback lockouts, especially on Ultra models, I encourage you to reply. This needs to be surfaced as a systemic regression, not dismissed as isolated app behavior.