I have BenQ DVD+R discs that smell terrible (yes, like it was burnt with a flame or something) - and these are brand new newly-opened discs. They smell better after using/burning and after a bit of exposure to the air outside of the spindle. And yes the smell does linger.
Burns and scans with each and every one is fine though. So I won’t be really worried unless every one of those smelly discs is a lemon. I have no clear explanation for it and have shrugged it off as a “manufacturing” by-product.
PS. I’ve also had Prodisc DVDs and CMC CDs that smells too, but I can vaguely remember if those were only of specific batches and not a constant with every spindle I buy.