By meal 3, the lion didn't drop any food while driving.  The oscillation still seems to be from friction in the steering.  Steering gain might have to be lower.  Meal 2 confirmed it was impossible to pour the food while holding the leash without the robot speeding up & getting ahead.  Meal 3 was the 1st with the waist strap.

It might be a pain in the mane to put on, but having 2 free paws while driving is a game changer.  An animal could probably leave the waist strap assembed & step into it rather than threading the cord lock.  You can't feel the robot when using the waist strap.  It provides more confidence than pulling by paw.  Lions are prone to move their paws in unpredictable ways.  

If it drives ahead of the lion, the steering deflects erratically & it goes out of control.  This is the 1 kaboom case.  It could happen going downhill.  There's some braking, but not enough to stop it from rolling down a hill.  It could happen in a case where the retraction broke & all of the leash extended.  Maybe another animal could run into the leash & pull it out.

Being on the subject of leashes, what most animals use are these folding wagons.

https://www.amazon.com/Sincely-Folding-Utility-Portable-Capacity/dp/B09HBJYKSX

As far as lions can tell, it doesn't have any steering or brakes.  The handle is on a separate gimbal from the wheels.  Forget about pulling it 20 miles.  It's not paw free like the waist leash.  It could form the basis of an off road robot.