このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語)：
progress bar not updating
対処
関連リンク
Javascript progress bar not updating 'on the fly', but all-at-once ...stackoverflow.com/.../javascript-progress-bar-not-updat...
https://stackoverflow.com/questions/5743428/javascript-progress-bar-not-updating-on-the-fly-but-all-・・・
Why doesn't Progress Bar dynamically change unlike Text? - Stack ...stackoverflow.com/.../why-doesnt-progress-bar-dynami...
https://stackoverflow.com/questions/30285185/why-doesnt-progress-bar-dynamically-change-unlike-text
Progress bar not updating the current time and remaining time ...github.com/videojs/video.js/issues/3881
https://github.com/videojs/video.js/issues/3881