I am looking at your pics....Your problem here does not have anything to do with your mold gates.... This is a viscosity issue. Hopefully you are using accurate thermometers. (probe style, not point and shoot style).
Colorant will act the same as softener which will speed(thin) the viscosity. So when shooting lams, if you have exactly the same amount of colorant in each color, the viscosity will be the same, so shooting within about 10 degrees of each other will produce a 50/50 lam. If one color has more colorant, the viscosity will be thinner(faster) in that color, so the thicker(slower) viscosity color will need to be hotter than the other to get a perfect lam because it will flow slower. This is not a perfect science, as there are many variables. i.e....If you use a lot of powder in one color and not the other it will slow the viscosity too.
I would bet you have more colorant in the darker color here. Try it again with the darker color hotter than the lighter color.