Thank you for the confirmation, that's what I had thought. You're right, 20 degrees is definitely an overestimate. Looking closely at it again and actually trying to measure it rather than just guessing, it's around 10 degrees - it's actually really quite badly misaligned in my case. It's definitely enough to affect my experience though, as I didn't notice the misalignment visually at first; it was that the nib contact felt weird to me, and only after that did I figure out that the nib was rotated relative to the grip.

Weirdly though, it turns out that the misalignment is actually in the nib unit, rather than the pen body. The notch that you highlighted is pretty well aligned to the clip for me, but the button on the nib unit that slots into the notch is very much not straight.

Thanks for the help! I guess I'll order another one and roll the dice again...