The Bell 407 FADEC will automatically start a record if there is an exceedance. it will grab the previous 10 seconds worth of data, and record for another 50 seconds. It should then be downloaded after landing and the whole thing looked at.
A mysterious exceedance would only show up on one channel (say torque) and not have any corresponding N1, TOT, fuel flow, etc to confirm there really was that much power being put out.
But be careful - the FADEC data only records data every 1.2 seconds!