Ok, some of my Italian friends have spoken directly with the pilot and found out what happened.
The aircraft is using a DJI Wookong-M flight controller. He must have painted the GPS black, I don't know on that yet. Pilot states that it began what appears to have been a "GPS Flyaway", while at the same time he lost remote control of the aircraft. It's not clear at this time if it was a simultaneous loss of RC Control and GPS signal (which would be odd) or if it was another instance of these DJI systems seemingly getting into a state where they are flying somewhere and ignore the pilot's inputs attempting to retake manual control.
If it was a true loss of radio control, why didn't the copter return to the landing point? If it was a true loss of GPS, why didn't the copter respond to manual controls? If it was a true loss of GPS and RC control simultaneously, why didn't it land straight down as they are supposed to? We're always left with these questions. DJI data logs don't provide enough information.
Now, in Italy, commercial operation require the aircraft to have a completely independent flight termination system which cuts motor power. This system operates on an independent control signal.
The pilot, realizing he had lost control and it was flying away, activated the termination system, which is why it crashed so heavily. He did not know that the skier was actually coming down the course at the time, so the timing of this event was just unfortunate.