Yeah, we've gone back to having to trust the brand name of the distributor - if it says it came from Amazon it is basically assumed to be counterfeit chinese crap; Costco and Home Depot (and even Walmart in store) are a bit more secure there.
Unfortunately, I've never seen information about how Walmart handles this. Given their massive shift to 3Ps providing most of their products online...I'd imagine they use a similar strategy (it improves same/next day availability and lowers cost). I follow the same strategy with Walmart (try to only buy directly).
It is a sad time for online purchasing :(