I can't say that I've noticed this "problem." The cruise control is supposed to disengage as soon as the stop-light switch is activated. This should take only a few millimeters of pedal travel. (At night you can check this by looking in your rear-view mirror. You can see the reflection of the high-mount stop-light LEDs on the rear window glass.) Mine does this. If yours doesn't behave this way, a warranty adjustment may be in order.

Stan

P.S. I've just seen finman's post. I think he's got part of the explanation! When you disengage cruise control by using a tap on the brake pedal, since your foot is off the accelerator pedal, the car will begin coasting under mild regenerative braking, which will cause a small deceleration lurch. You can control the extent of the lurch, and whether it's forwards or backwards, by first feathering the accelerator pedal (2-footed driving); or better (1-footed) by using the steering-wheel lever to disengage the cruise control, after first feathering the accelerator.