In the case of the counterfeit copies of Linux Command Line sold through Amazon, those were printed by CreateSpace in violation of copyright. That is certain. From what we can tell that is also the case here.
If you don't mind me asking, is there a POD block printed on the bottom of the last blank page? Typically it's a barcode and something like "Printed in USA, Lexington KY" and the date.
Also on the Twitter thread someone mentioned that the contents were copied from a PDF you sell on the site -- are they the same press-ready PDFs used for the book, or PDFs formatted for 8.5 x 11? I ask because we sell PDFs too for letter-sized paper, and I always assumed it would be difficult to pirate for a 6x9 how-to guide.
It's possible it's someone doing digital short run and then selling it as a third party seller. If the price is low enoughI think that helps them get the buy box.