Because of the incredible high ink-load of Piezography relative to any other monochromatic ink systems, some bronzing on some papers is inevitable. Generally bronzing is most noticeable with window-light at a 45 degree angle. If this particular paper/ink combo is going to be shown in window light and not behind glass or anything else, than this could be a slight issue with this paper and other papers like Hahnemuhle Photo Gloss Baryta may be needed. If not, I suggest putting the printer under gallery flood and view it at the same angle to verify under display conditions.
As above poster said, other interactions between residual pigment/ink/paper-type can effect it as well.
best,
Walker