Also Oda dead ass forgot to draw Sabo's scar once
He never fixed this btw.
Oda makes a lot of mistakes with the drawings. Pair that with the fact that he was struggling with astigmatism for a while, as he said in 2023 that he "talked about it since last year" which would be 2022 obviously enough
https://x.com/WSJ_manga/status/1665951861877391361
That lines up with the date of the chapter Aramaki was introduced in. So his eye sight back then was evidently kind of shit, as seen with him outright coloring G5 Luffy's fist white and not black in a page during his fight with Kaido. If a fuck up like that is possible, then him drawing Aramaki's blade wrong is definitely possible, though it is admittedly strange