Birddog
I am not a CPL and compared to many guys here my hours are low. Here is my view, but I welcome any more experienced PPrune member to correct / improve.
The rapid accellaration of yaw effect can be generated in gusty conditions or it can simply be a result of turning through the wind thoughtlessly. It actually happens to some degree on every turn to the left, even in mild wind, but mild wind = smaller additional torque force hence small accelaration. Control is simple, though the distance that you need to move your right foot can catch out somone unused to the machine. Practicing left turns in (first) little wind and (then) slightly increased winds (and stopping before the wind strength means that you do something daft) will show you the effect, and how the yaw rate effect increases with increasing windspeed.
Turning left through a high wind brings significant additional torque load onto the tail due to the sail area. Accelaration in yaw can be high; literally "stunningly so" for some people in some conditions. If your mind is not ahead of the aircraft (if it was, why were you turning left through the wind in an EC120 / Gazell / Guimbal / etc?) it may startle you and your reaction may be slow; perhaps some people even freeze. The accellaration in yaw is rapid. It can reach a sufficient rate of yaw (before your control inputs begin to have any effect) to buld the momentum to take the machine through a full rotation - weather-cocking and your right boot will bring it to a halt but it may not be until the 2nd or 3rd full rotation if your reaction to the initial yaw is not quick enough. During that time your job is to keep it level and away form the ground / other expensive objects. Not as easy as it sounds with a rotation rate that might have reached 30+ RPM.
Training mantra "To the right, avoids a fright" is best followed. Don't use a left turn unless you have considered the wind direction and strength, remaining power available, and when to begin the anticipatory right boot movement (it is best to be increasing the right boot before you put the tail through the wind).
The aircraft is perfectly manageable; it just requires that you understand its characterisics and limitations and fly accordingly. Personally, you may never get me out of this model; except into a Guimbal once I cannot afford the EC120.