MicroSD card dumped files onto my Moto E4?

[GanChan]

I bought a Sandisk Ultra Plus microSD card to expand my Moto E4's capacity. I bought it, not online (because I'd heard about the knock-off risk), but in-store at OfficeDepot, in original packaging which appeared correct and untampered with. Even so, when I installed it in the phone, I later found a bunch of odd files -- generic photos, music files, and even something that looked like presentation slides. I deleted the files from both the phone and the card, but -- what the heck? I'm assuming these weren't "demo" files of anything was actually supposed to be on there....