I don't think the artist got the memo of He's Constantly Using Clear Mind at 100%. Like, one of the biggest hurdles in the early arcs is him learning to stop using it so much, because while using it, he doesn't feel emotions: Period. And that starts to affects him even when he wasn't using it.
One of the humor points, is that he was unfased by really erotic situations, because... he just looks at them logically. In the LN, he is genuinely confused why they're sticking to him so much, not flustered about it.
TLDR: He straight up doesn't feel embarrassment, so they should stop drawing him as if he does.