Or an over-zealous recovery, lowering the lever and pushing the cyclic forward followed by a check back on the cyclic to control the nose-down.
Simply lowering the lever too quickly will reduce positive g and can even take you to negative - we all know the dangers of that in a Robbie.
On a high inertia rotor you are absolutely correct. On the RHC, in the OGE hover the recovery time is minimal. RHC estimated a tau of around 0.7 seconds for the R-22, which is shorter than the response time required under the FAR for test. It was accepted on the basis that as it is a critical manoeuver the pilot would respond immediately. The R-44 has a better tau but is still not long, the response to an OGE throttle chop is an immediate descent and a rapid loss of Nr. For the R-22, I recorded in an STC series an OGE Nr drop from 104% to 89% in 0.5 seconds, with no perceptible dwell time on the collective. The attitude was recorded for the test helicopter, as well as accelerations, around the CG, blade root loads, both bending and torsion loads, and pitch link loads. Stall Nr was measured for the stable IGE hover at 82%. The mod lowered that to 78% and one configuration got that to 68%. For a Robbie I doubt that anyone teaches or does a delay in lowering the collective in an OGE throttle cut. lowering the collective rapidly itself doesn't give much of a pitch change, the yaw pedal input makes more of a difference to the trim and to the attitude if not corrected quickly. FWIW, my own view is that OGE hover in the RHC is not for the faint-hearted or anyone who is not up to speed. It is required to be trained which apparently this incident was a training flight.