@TeamYouTube Can you just have auto-play as a switch you can control for the Watch Later playlist? It's stopped auto-playing again, and my friend has had it happen to them as well.
While we don't have the feature yet, you can share your thoughts by sending feedback: https://yt.be/help/XrMG . Also, could you confirm what device are you on? Try signing out and signing back in to see if that makes a difference. Keep us posted.