I’ve noticed that some have complained that they aren’t seeing videos in posts. And I’ve noticed the same thing myself. I hadn’t worried about it much since, for the most part, the videos weren’t critical to the subject - at least at my level of interest in the topic. Discussion around unviewable (for some) videos revealed that they were all mp4s.
Although, for me, the option that appeared when I right clicked was “Open video in new tab”. In any case, a new tab (window) opened and the video was visible and playable.
Just want to share this in case others were looking for a workaround.