If you think about it, even though the tire does not have the normal force / contact patch. It just touching and rotating on the ground still provides direction stability.

Imaging taking the RC wheel and just barely running it across the ground. You'll still get a guiding force that is consistent.

Now imaging your car with the tire momentarily losing contact with the ground. In a turn the car is slipping (slip angle on the remaining 3 tires) so as the tire comes of the ground and regains contact the vector that it was traveling is now offset lets say 5mm. It is that regaining of contact during the slip of the car that might cause instability.