Overpitched' Good question!
I have myself been to 110% Q on the "L" model without experiencing any RPM drop and a colleague had a 123% Q overtorque (UMS fitted) to avoid obstacle and he said he never experienced loss of RPM and the UMS agreed, it showed a momentarily decreaso to 98% Nr and the RPM was actually back up to 100% +-0.8% by the time he reached 123% torque.
The helicopter was a 206L with Allison 250 C30 engine.
Nedless to say it had to have complete inspection and overhaul to its rotating components and was out of service for 3 months but at least he didnīt crash it.
Someone above mentioned that the pilot may have on purpose let the helicopter spin to the right. That is an often used procedure on the 206L to avoid overtorque so I agree that it may have been on purpose and the aircraft may have been experiencing a power failure or power loss i.e. stuck PC valve or similar problem where you dont really hear the turbine winding down or engine out warning.