https://wccftech.com/google-fixes-broken-seek-bar-with-youtube-v13-28-54/

Of late, Google’s updates seem to do more harm than good. The July security patch slowed down some Pixel’s wake up time and a recent YouTube update did something similar. The update doesn’t bring anything in the way of new features. On the contrary, it breaks one of the most fundamental feature essential to any multimedia application. After the update to version 13.27, you can’t tap on the seek bar to go to a different location in the video. Essentially, you’re stuck watching the video in a single go. Not something one would expect from YouTube, of all companies. Upon discovery, YouTube acknowledged it and said a fix was en route.

If you're using the YouTube app on Android, we're aware of an issue with tapping on the progress bar to skip forwards/backwards.