This is one of the best explanations of what to do to help prevent caravan sway.

https://www.caravansplus.com.au/guides/how-to-stop-your-caravan-swaying-must-see-video-a-4.html

They don't quite understand it.

This is from Bath University in the UK. A much better demonstration with ball weight maintained correctly.

A combination of speed and high yaw inertia (weight at the ends) makes for instability.

https://www.youtube.com/watch?v=PFzrWHTG5e8

Cheers,

Peter