Are you sure that the ECN-2 process uses CD-3? At one time it used CD-2.
Also, regarding ECN films, they are built to a contrast value of 0.5 as opposed to professional and consumer negative films with a gamma of 0.6 - 0.65. Therefore, the print material for ECN films has a higher gamma to yield an equivalent positive image.
The normal printing process on Endura or CA paper would yield a print with low contrast and low color saturation and is inappropriate for the ECN family of films.
Use of the wrong developing agent would further reduce contrast and color saturation so please check on that. I have not looked up the ECN formulas in years, so I may be wrong OTOMH like this.