Around Dunajske stutters at certain points

I’ve tried downloading Around Dunajske a couple of times and it plays fine in a browser. But during a ride (using Apple TV), it stutters at certain points. Most of the time it’s the same point in the video, but once in while it’ll stutter in an unexpected point. For instance, it always stutters right at the beginning where the rider crosses the blue bridge. And then at the first 90 degree right turn and then the next 90 degree left turn. It also stutters whenever the rider slows for a gate or a car or some other obstacle. Otherwise it plays fine. I’ve been using Fulgaz for many years and I have several dozen videos downloaded and running off a NAS. This is the only video I’ve ever seen do this. I know when your relative speed drops below the 80 percent mark, the video will slow a bit to keep you synced up. This is not that. This is stuttering, like the video drops to 2-3FPS for a bit. Again, the videos play normally if I just bring them up in a browser. The stuttering only happens during a ride using the app on Apple TV.