The bags i've purchased from there that have been described as "having a smell of mould" etc have had a slight smell of mould but it wasn't severe and by opening the bag and letting it air for a couple of weeks it vanished.
Some smells come from the fact that their country of origins' humidity levels are high thus inducing smells, and, storage areas don't have as free flowing air circulating - by reversing all these conditions the smells disappear quite quickly.
I've bought bags elsewhere that have had musty smells because they'd been sitting in the back of someone's wardrobe, unused, for ages .......
Just air them well - they'll be fine when they're done.