YouTube block doesn't show YouTube (Catch Box 4.8.2)

Hi, My site uses WP 5.1.1 and Catch Box 4.8.2. I insert a YouTube block in my post. In the edit window, YouTube's thumbnail appears, however, in my post, YouTube doesn't appear. I changed theme to TwentySeventeen tentatively, YouTube appeared in my post. My post is https://chokowalk.sakura.ne.jp/n02/test/ Is this a bug of Catch Box 4.8.2?