There were not in vortex ring state. The Blackhawk requires a rate of descent in excess of 1000fpm to get into vortex ring.
What a fantastic statement. So have you downloaded the data recorder to confirm this? How many hours MH-60 do you have and at what Hd and airspeed is that 1000fpm correct? My point here is that you are coming across as a know-it-all and i'm afraid you don't.
I have not said it was VRS just that settling with power is the US term for this. I would, however, agree with Turtles comments as to the most likely cause.