Bug Report: **Environment Details:** * **Device:** Samsung Galaxy S25 Ultra * **OS:** One UI 8.5 (Android 16 base) * **App Version:** YouTube App v21.20.402 ### **Issue Summary** The primary top-bar "Cast" icon is entirely missing upon initial application launch. The user is forced to actively play a video in the mobile player interface just to surface the Cast icon. Furthermore, once a casting session is successfully initiated via an active video, the application fails to maintain persistent session state. Clicking a subsequent video breaks the casting pipeline—the new video plays locally on the smartphone rather than prompting the expected playback or queuing options on the active display. ### **Steps to Reproduce** Launch YouTube Observe the header bar on the home feed ( Cast icon is missing). Tap on any video to open the native mobile media player layer. Tap the video player to display overlays; tap the newly visible Cast icon and select the active TV device.…