If the icon appears to be moving sideways, it doesn't mean the real airplane is moving sideways.
On the other hand, if the icon disappears suddenly altogether, what is really happening is dependent on the software driving the display. For example, when the aircraft is at around 400' height above the ground, the image disappears, but the actual aircraft just dropped "below the radar" on landing approach.
The image of a real air traffic display would be much more useful, but I doubt we will ever see that posted on the internet until long after the accident investigation is completed.
I know. That’s why something like this cannot be a “smoking gun”. The guy obviously thinks he’s found proof of a conspiracy, when all he’s done is exposed the inaccuracy of civilian, for-entertainment-only, flight tracking websites.