Sensors.
We had the same problem at Ek. Lots of Hard landings.
They found that the sensors that detect a Hard landing where too sensitive and where giving false readings.
Solution:- Turn the sensor off and let the pilots decide if it was a hard landing.
Problem solved.
However they have decided to turn the sensors back on I believe about a week ago.
Result:- 4 hard landings and counting.
Go figure.