[the NTSB says] some of its five composite main rotorblades appearing to drop from their normal plane.
Quote coming from the Flight Global article :
https://www.flightglobal.com/news/ar...ed-bel-428027/
It could be a misunderstanding from the journalist but when NTSB says "some", I'm pretty sure It does not mean "all".
@henra : What you say is interesting: a retreating blade stall can result in the rollback of the entire rotor ? So the maximal loss of lift is on the back of the H/C (the phase shift is still applicable) ?