Amazon's fulfilment system co-mingles. Checking the seller is pointless, it is an accounting thing only. If it's fulfilled by amazon, then the source can come from _any_ FBA merchant.
It still specifies "fulfillment by Amazon" in the text under the price, though, implying they aren't selling it directly.
A clear indicator that it's directly from Amazon and not intermingled is "Ships from and sold by Amazon". Any mention of fulfillment in that text should make you slightly more cautious.
Obviously, this entire situation is stupid and they shouldn't force you to parse their little blurbs about selling/fulfillment, but the information is there.
You have to check whether the item is being sold by multiple sellers and whether or not they are using Amazon for fulfillment. I never buy anything if it’s not sold by Amazon AND if there are multiple 3rd party sellers who store their inventory at Amazon.
A clear indicator that it's directly from Amazon and not intermingled is "Ships from and sold by Amazon". Any mention of fulfillment in that text should make you slightly more cautious.
Obviously, this entire situation is stupid and they shouldn't force you to parse their little blurbs about selling/fulfillment, but the information is there.