From BH site.
All items sold by B&H are warranted solely by the manufacturer/distributor, except "direct import" a/k/a IMP items. All items needing repair (other than IMP) should be sent to the manufacturer/distributor directly for service. B&H is not liable if the manufacturer/distributor fails to perform warranty service
You need to send it to Canon, being in warranty they will even cover the shipping I believe. But BH would take it back for a return or exchange of the whole thing, since you bought two, they give you 30 days to return anything, but cameras need to have less than 200 photos according to their "small letter" on the returns.
I bought once a lens that arrived not working correctly and they took it back even paid the shipping, so that sort of contradicts what it says on their website. So you can give it a try, but as it is already 30 days.....
You must be covered in any way. Hope you get it solved soon. Don't wait, it is not normal.
I've seen it it filters that are thick at 24mm but is usually the same on each corner.