The video on the linked page started playing, verbalized the first few phrases (ending with "... recent years") and then went silent. The video kept on playing

The video on the linked page started playing, verbalized the first few phrases (ending with "... recent years") and then went silent. The video kept on playing, the subs were changing, you can hear the original (muted down) soundtrack, but the narration audio was gone. Skipped forward by a minute or so, the narration resumed and then again stopped once the current subtitle was exhausted. Subsequent dragging of the video slider made no difference, the narration stayed off. The dev console shows "Uncaught (in promise) DOMException: The play method is not allowed by the user agent or the platform in the current context, possibly because the user denied permission." popping up, seemingly randomly, both when the narration was playing and when it was not. This is in a recent Firefox on Windows. PS. FWIW, the quality of the narration is really good.