Older aircraft, H-19 (Whirlwind in British vernacular), H-34 (Wessex in British vernacular), Chinook CH-47A, most any helicopter in reality can be pushed hard and encounter Retreating Blade Stall.
The commonly accepted indications of that is pitch up and roll left (thinking American direction of rotation) with a high forward speed, high Density Altitude, and/or High Gross Weight.
That does not work for the Tandem Rotor design....depending upon which Rotorheads enters RBS first.....usually what is felt is large increase in airframe vibration and a loss of performance re acceleration, climb, or airspeed.
I have experienced RBS numerous times (for varying reasons) and never found it unsettling due to the amount of upset.
Perhaps I reacted upon feeling the increased vibrations and being aware the aircraft was approaching the calculated One thus I was aware of the possibility of RBS being encountered.
The normal reaction of a helicopter pilot, even if not awake enough to understand what is going on, is to reduce Collective and as a result....slow down slightly.
That seems to be a natural reaction for most unusual events and is just something that is ingrained after flying helicopters for some period of time.
That observation is derived from the days we hand flew the aircraft all the time as Autopilots were not installed on what we were flying.
As RBS is directly related to Airspeed....and generally (depending upon the aircraft type) gives warning in the form of vibrations and other easily observed reactions....the pitch up alone is enough to slow the airspeed and if followed by a reduction in Collective....normal flight is easily attained again.