Video placeholder remains on the lesson page

Using Masteriyo 1.4.1 in WP 5.9, I created a lesson page in a course. There were a few sentences in the text field and I also added a video from my computer (not from YouTube or Vimeo).

After a while, I decided to delete the video from this page and saved the page again. Now, when I preview or visit the lesson page, there is a huge gap between the lesson title and the page content. I tested this with different browsers both in localhost and in the internet. Apparently, this huge gap is where the video should have been. Removing the video file from the “Media” section does not solve problem, either. The only solution I can think of is to delete this lesson page and recreate it. I believe this is a bug that should be dealt with.