Cruise Control problems of the 2021 Tesla Model Y

At random times, without warning, cruise control changes from set speed (e. G. 70mph) to 45mph and vehicle immediately begins hard braking to achieve new set speed. Any cars following may not be able to react quickly enough to avoid a collision if the driver doesn't react quickly enough to command acceleration back to freeway speed. I sent multiple videos of this happening to Tesla's service department. Tesla virtual service has looked at vehicle's logs and says there's nothing wrong with the vehicle and that it must be in how the vehicle is interpreting fleet data and map data. Clearly a software bug not validating it's input for reasonableness. No audible warning and while the cruise set speed does change on the display, the deceleration happens simultaneously, so no actionable visual warning is given to prevent the uncommanded deceleration and one must react immediately.