Amazon motorex oil different than dealership oil

So when I picked up my norden I got a few quarts of oil and a filter
I changed the oil at 200 miles and she had a good bit of metal shavings and the magnets in the drain plugs were pretty packed
But I bought a 4 quart jug off of Amazon for my next oil change at 600 miles(the smell is what grabbed my attention) I noticed when I opened the big jug from Amazon that it smelled really strongly almost like gear oil so I had the single quart jugs left from the dealer and I compared them and there is DEFINITELY a difference ! Could this be from age or something
The big jug was sealed and everything I also looked into the seller and they have good ratings they have a place in so cal I guess
I’m tempted to return it and just take a ride to the dealership and buy some singles