Problem with Jumbo Jet VIP Expanded for Iray
andreretogasser
Posts: 256
https://www.daz3d.com/jumbo-jet-vip-expanded-for-iray combined with with G3f and with G8f makes dark spots on the forehead! Someone knows how to fix the problem?

Comments
Are the figures away from the origin, especially backwards (negative on the z axis)? If so try parenting everything else to the focal figure and then move that to the centre of the world.
Not quite sure if I follow your train of thought correctly .. I will couple and center everything on the scene tree. But I will not have time until the weekend.
Try expanding the hair cap as well (select the hair > parameters > look at the morphs and there should be one regarding the hair cap). That usually fixes it for me.
Updated to add: another fix is to go into your render settings and change "instancing optimization" from auto to speed.