Why do videos within courses randomly disappear and how do I fix this?

I have been working on the full stack development course, but there is just a minor inconvenience that sometimes the videos for the lectures aren’t there anymore and the lesson is only available as an article or transcript. Now I understand that not all lessons may have videos but this current topic I’m on which disappeared definitely did, “How do width and height work” from within the set of lectures in the “Basic CSS”, had a video and I know this because there was a video which showed the previous day but I didn’t watch it as I done my study for the day, but the next day the same topic doesn’t have a video.
I know its only a minor inconvenience and it doesn’t really matter for simple topics but I really find the videos useful for more advanced explanations. If anyone has a solution or knows why it’s happening please let me know.

The videos became too time consuming for the team to maintain and had to be removed.