I'm not sure if this would be because of voids. If it was you would be able to crack the gelcoat in that area by applying pressure to it! I would say that it is more likely colour separation in the orange pigment of the gelcoat. This can be common in orange and red gelcoats through no fault of the boat manufacturer! Unfortunately it is undesirable and there is very little that can be done with it.
Pigment separation can occur in other gelcoat colours but orange and reds seem to highlight the problem more because of the contrast in the colour!