T and B,
Are you describing a nose tuck to the right during a hard banking turn to the right....which increases the rate of turn and an increase in the rate the nose dips down into the turn?
A remedy for that is full. opposite pedal...in a right turn meaning full left pedal to the stop until the tuck and turn are remedies by the nose picking up and the rate of tun decreasing.
Adding collective would require the input of left pedal to counteract the increased torque and if only enough was used to balance the additional torque the nose would still drop.
We encounterd the same response in both the 105 and 117 and used the same recovery technique taught by the Factory Training Pilots during our Annual Factory Training..
An operation I was on lost an aircraft due to that....a low level steep turn to the fight with an increase of Collective caused the aircraft to experienced a nose low pitch attitude and an increase in turn rate which was aggravated upon the pilot increasing collective setting in an attempt to counter the rate of descent.....the aircraft was written of and only minor injuries to the Pilot and Crew were sustained.
That proved the need for annual third party training which we undertook by contracting with the Factory by having Annual visits by their Training Pilots.
I would imagine that might apply to most helicopters.
Perhaps Brother Dixson could expound upon this for us.