I had a bizarre oversteer event in my 996TT once. Cold temps, coasting at moderate speed through an off ramp, rear end starts sliding out until I'm nearly sideways. Never noticed any PSM attempt at correction at all, my steering kept the car on the road. This dramatically contrasts with the aggressive PSM action on accelleration oversteer (throttle cut and front tire ABS pulsing) that I've had and would expect in the situation described here. Kind of makes me wonder if PSM COULD intermittantly fail.