Here’s a neat video of Io and Europa filmed as they fly over Jupiter’s Great Red Spot. It’s of course speeded up but what a gaudy view that would be. It reminds me of some of the scenes in Heinlein’s “Farmer in the Sky” when the boy is figuring out time by where the moons’ shadows are on the face of Jupiter.
What little I know of orbital dynamics includes the fact that a lower orbit has a higher velocity than a higher one. For example, you need to be moving at approx.17,000 mph for low earth orbit but a geosynchronous orbit is is only around 6,300 mph.
The video shows the higher moon passing the lower one. It could be a parallax illusion but probably not because their orbit radii are very close to the same.
I noticed that too but couldn’t think of any reason. I hate to think JPL is faking this.