If it resembles anything at all, its possibly sulphur shortage. If you look closely, there is evidence of other, faint discoloration on other leaflets in that leaf, presenting mostly as lighter green parts, as opposed to the distinct yellowing. It might also be a viral infection, hard to say. The first link below is a diagnostic site for hemp plant nutritional problems, but doesn't cover viral infection, the second link is to a site showing a plant infected with Tobacco Mosaic Virus and what to do about it... it doesn't exactly look like TMV currently though.
http://www.thenug.com/galleries/diagnose-your-sick-marijuana-plants
http://bigbudsmag.com/dealing-with-tobacco-mosaic-virus-tmv-br-in-your-marijuana-plants/
You haven't said whether this crop is indoor or outdoor, hydroponic or not, but both links might be of use anyway.