I have also experienced this problem.
It rocks my 15,000 MH back and forth. It will not stop until you bring the coach to a complete stop.
My research has found that it involves different coaches (Gas and rear diesel), different brands of towbars, different brake systems. It happens under different conditions (interstate, city, straight road, turning, etc.)
The only constant is the 2014-15 Jeep Cherokee.
I have filed a complaint with www.nhtsa.gov/
If you have this problem, please file a complaint so they know it isn't an isolated incident.
I have towed in 46 states. I have had a Jeep Grand Cherokee, Wrangler and Liberty. These are different vehicles. They are basically a rear wheel drive platform. The Cherokee is a front wheel drive platform. (I don't think that Chrysler/FIAT had this vehicle properly sorted-out for use as a dinghy.)
Thanks,
John