YouTube said that it is testing a video progress bar redesign for its Android app that is not red at all times. In October, YouTube initiated a redesign phase across its app and web.
When a user is consuming YouTube videos on the an Android device in dark mode, the progress bar is either white or grey instead of the usual red colour. In such situations, YouTube is also not sure how much of the video has loaded.
By tapping on the screen to bring up control changes back to the previous, the loading process is completed and helps the UI to fade away. YouTube has been working on this situation with the Ambient mode.
The usual red colour of the video progress bar is still there outside of the video player in the main feed.