I feel like I'm usually pretty in-the-loop about the shit Amazon pulls, but I had no idea about this one: https://bsky.app/profile/jomc.bsky.social/post/3koey5rojww2b
It's a whole thread, but basically, even for traditionally published books, Amazon will often send you a very cheaply-made print-on-demand copy instead of what you actually ordered. With no indication that this is what happened unless you know what to look for, and (of course) no discount.