After recent updates, a slide that uses local html video for a background is not working properly. The video is showing a first-frame preview with a native player icon, but the slide text/button is not displaying above it. The video cannot be clicked.

embed code:

<video width="640" height="360" preload="metadata" autoplay>
<source src="/wp-content/uploads/2021/02/food-processing-video_1.mp4" type="video/mp4">
</video>

"background video" is enabled