Thanks for the input, I'll be doing a DoE soon. We have a smaller screw for the machine that is a barrier screw designed for acetal, but the supplier was not able to install it while they were here due to them missing (forgetting?) some parts.

For an update, we tried a different color that is a standard concentrate in pellet form. This eliminated most of the color 'swirl' issues we were seeing. However we are still seeing some discoloration across the knit line in a few of the cavities. It is not always the same cavities but it does seem to more frequent in certain cavities. Our next step will be investigating the hot runner, and older system from Mold Masters.