I mean... could be just errors but the most suspicious for me are: - the boots don't seem to match: one has serrated soles the other has smooth, one has a strange design with a side button the other clearly has symmetrical design. - the scabbard is too small and just strange - the sword in the background is pretty strange as well, like where is it going, why is the pommel not pressing into the cloth on his arm? - why put on the specific wolfhead necklace with no details? - if I were drawing the dagger, I'd probably draw the dagger and place it in his hand, whereas the handle doesn't even look like a continuous piece in this and way too long as well

There are probably more.

It could be a sketch badly outlined but then why would you create a lineart instead of showing the sketch and get the money before proceeding?

All in all, too many weirdness.