You're right in that Streamlines are a "stepchild" deck, inherited by USPC when they bought out Arrco.
I think I know the situation here. Remember there was a big event in USPC history in 2009, right around the time these decks were being made. The company headquarters in Erlanger was "christened" August of that year. Even Bicycle decks have been known to have a mismatch between what was printed on the box and what was printed on the Ace of Spades for decks released in that year, but for them, it was mostly the other way around - classic-style boxes that said Cincinnati, Aces of Spades that said Erlanger. In that case, the telltale for knowing the difference was the box seal - black boxes seals became standard issue in Erlanger, so a classic-style Bicycle box with a black deck seal almost invariably contains a Kentucky-made deck.
It's entirely possible that the cards were printed in China before the official changeover but the boxes were printed after, resulting in the mismatch. It's also possible that whoever was responsible for the graphics didn't catch the Ace of Spades not being updated until after the cards were printed.
And they're definitely Canadian-issue decks. The American ones don't have the French wording on the boxes along with English.
I can say this, however - by 2010, USPC had stopped using their Chinese printers for all but their Maverick brand decks. I own Streamlines very similar to these with a 2010 copyright date on the box that state they were made in Erlanger. They're actually quite good quality, on par with smooth Bicycles.
I also noticed they passed the "stone test" - where I work, we have a desk made of stone that tends to be cold in the winter months even though the space is heated. In the cold, the top cards in a stack of cards will have a tendency to develop a slight, temporary warp to them. My 2010 US-made Streamlines, however, didn't bend at all. I suspect it has something to do with the smooth surface - greater surface integrity leads to a stiffer, less-vulnerable card. I've noticed that Ivory Bee decks tend to be a lot more stiff than Cambric Bee decks - same thing, Ivory is smooth, Cambric is embossed, and the embossing is created by pressing steel rollers with many teeny little bumps on them into the surface of the paper, in essence "damaging" the surface.