I don’t know the science behind it, but it seems to over produce oils and takes a couple weeks to normalize. During that period I was showering once in the morning and once at night, again running my fingers and water through my hair for ~2-3 minutes straight. After a while my hair didnt get so greasy.

i think it might just be that it "feels" greasy, as you move from using shampoo, to not, but as you move from not using shampoo to using shampoo, you'll notice how dry your hair is after using it, and if you condition you'll notice how "greasy" it is as well.