Last week around Black Friday Amazon was offering a $21 coupon on top of the $140 sale. The shield was out of stock so orders were delayed.
Once the order processed for me the $21 credit was removed and the total jumped up, so now I have to reach out to Amazon support.
I have a feeling this bug affected other orders as well, check your receipts!
I've seen users report similar with Nintendo Switch items to. Sadly I don't recall what of mine had coupons on and what didn't.