Robin Son.
No experience with paper quality but for a product like chocolate I could imagine receivers might be choosy.
Food odour, and various other organoleptic characteristics, is notoriously difficult to standardize, even internally. Hence trained evaluatiion panels. Some people simply have different olfactory capabilities.
Based on yr post, the odour aspect should have been clearly defined in the (agreed) product spec. and an acceptable/unacceptable sample demonstrated.
Management often regards this as an unneccesary, time-wasting hindrance to business but once you've experienced a few QA disasters and found yourself in the middle.......
Regarding complaint, sample request is usually the first step followed, depending on the results, by overt "challenge" or "damage limitation" (some companies always challenge anyway, the "nothing to lose" principle). The commercial response may also depend on any desired future business, or not.
Rgds / Charles.C