Its a fact HHKB feels scratchy, i ve mentionned it earlier, its not a good term to explain it
its a sort of friction underneath your fingers
Normal HHKB does have it but its less noticeable than silenced HHKB, i dont own Type-S but my silenced HHKB feels scratchy on some keys, not all of them
Live with that, there is nothing you can do, its pretty NORMAL
I also own a silenced NT, much better silenced feeling, i must say, less friction, better typing experience overall but HHKB has its own charm which i really love (its more ergonomic with some inclination, the bottom of case is lower than the upper of case, i simply prefer inclined keyboard than flat keyboard design)