Even with the parking brake set brake accumulator pressure decays over time. That's why aircraft should be chocked.
I understand there were no RYR movements at CIA because of Italian strikes (again). An unattended, unpowered aircraft wouldn't jump its chocks in anything less than severe gales, which there were not at CIA. So you have to wonder did CIA ground handlers remove the chocks from this one, perhaps to use on another arrival?
I suspect this will go legal. That damage looks bad and is not necessarily localised to the horizontal stab. Expensive for sure.