from what i can understand, the shadow is a little more visible when DE shaving than cartridge because the cartridge pulls the hairs up and then cuts below the skins surface (which is what causes alot of the irritation) whats your routine? i know if i spend too long in the shower before my shave then my skin gets a little swollen (hard to describe, not visibly swollen but i guess just the heat and water causes the pores to expand etc) if i then shave with my skin like this as my skin returns to normal my shadow becomes marginally more prominent, which is why i favour shaving mid shower.
"Whenever I'm faced with a decision, I ask myself 'Would an idiot do that?' and if the answer is yes, I do not do that thing." Dwight Schrute