After the June software update, users are reporting that 8K video recording using the high bitrate mode is no longer available. The option in the camera menu is still there, but the toggle is grayed out. There’s no mention in the changelog nor an explanation from Samsung.
Some believe that the high bitrate option was disabled due to stability issues. Users reported that sometimes recording 8K videos would result in stuttering and videos appear choppy. Perhaps that’s why Samsung decided to disable the feature until it finds a way to resolve the issue.
Either way, it would have been nice for Samsung to mention something in the changelog or release a statement. Still, the 8K recording as a whole is available, but at lower quality.