Misclassification – case 1. A “VVDS flag 1: very unreliable redshift” is predicted by the classifier in the new category “C5” for very reliable redshifts. The spectrum displays very low noise components that reinforce the confidence in the measured flux pixels. However the extracted 1D spectrum appears distorted considering the initial 2D spectrum. The extraction 2D → 1D induced a bias in the estimation of the (falsely unimodal) zPDF.