Two different experiences developed the same bug

I have had a recurring issue where a previously well functioning experience no longer works correctly. What happens is the background is no longer transparent and when you move to the next element the image in that element is not visible. I am including a screenshot of the experience and a link to the video that shows what happens when I test the experience. This happened with another experience. I had to recreate it and then it worked fine but this is the second experience its happened with and I’m wondering why.
Here is the video: https://youtu.be/ffSAZ2TsPY0