Yes, they haven't really got the wording right at all.
In this sentence
This may occur when a pilot attempts to arrest a rapid, low power descent only to find that he has insufficient power available to bring the helicopter to either a hover or a no-hover landing without exceeding the engine limits. However, this is not a vortex ring situation.
they didn't need to put 'rapid, low power descent', just the word descent would have been clearer.
Similarly in the overpitching sentence, this
This is where the pilot rapidly increases collective considerably and the engine cannot produce enough power to overcome the large, swift increase in drag on the rotor system
doesn't need the words 'rapidly, considerably, large or swift' in it