The Patterson film is full of surprises when subjected to close inspection. Here’s an example. Watch the animation as it runs. Click on the image to animate it.
If the sand bar were properly exposed, we could see that this print, or in this case “half print”, is not on level ground but on a spit of sand that pitches it toward the camera. Is this a footprint? Well…it’s in the place where the other foot would likely have been. You be the judge.