Okay, I found the issue. It looks like one of the video files didn't get copied into distribution project for this scene.
I do my best to make sure everything is synced up, but with 30,000+ files, sometimes stuff gets missed (and doesn't throw an error or get spotted in testing). So, fixed, and the bugfix file is attached (containing just the missing video file in the folder structure).
What is really odd is that this scene has been broken since the it first went out in r3.8... back in May of 2023! And no one else noticed or let me know the problem was there. But it will be fixed going forward. Or, now if you download the patch (I'm not gonna put in the OP, as again, no one even noticed until now).