Why it makes skin visible in predator mode and little bit more "red-ish" when trying to change the invisiblity setting?

Is this correct forum?

The skin goes red-ish because the colour of skin becomes mixed with the usual flesh colour - this is why setting your skin as white doesn't work. I don't know why it makes your skin become visible in predator mode though.

I don't think it would make sense that it comes up in peditor mode (although I know it does), so I'm going to take a completely random guess and say that Michal added it so's all the people with invisible heads would try and come up with a more original soldat color scheme.