Video poster image is not shown after video has been played

[marowi]

The poster image is shown correctly before the video starts. When the video has been played, it can be restarted. But then the first frame image of the video is shown instead of the poster image. It would be great if the poster image would be shown again.

This is how the video was embedded:

[video width="960" height="540" mp4="https://mydomain.com/wp-content/uploads/2021/07/video.mp4" poster="https://mydomain.com/wp-content/uploads/2021/07/video_thumbnail.jpg"][/video]