Haven't flown the 330 but I beleive that like the 320 it still has idle "open descent" as one form of selected flight and that the normal managed descent mode is '"des" which is based on a repressurisation segment followed by an idle path. I haven't seen the video but one explanation for non idle descent other of course than atc maybe that the descent winds were not put in or the descent wind changed to a stronger headwind.