When an advertisement fails to cleanup after playing, the advertisement’s transparent overlay will remain on the channel along with the word “Advertisement” in the top left corner and the href to the advertisement landing page.
Video player extensions (overlay and components) will not load when this happens. The viewer will have to reload their browser to cleanup the advertisement and restore the extensions functionality.
Using the latest version of Chrome (Version 71.0.3578.98 (Official Build) (64-bit)), surf through channels playing advertisements until the advertisement stops. You should see the word “Advertisement” in the top left corner.
Make sure the channel has video player extensions active to reproduce bug.
Even when you surf to other channels, the word and clickable landing page remain. You have to reload to remove and restore video player extensions.