At the last meeting of the screenwriters group I belong to one of the members who runs a mirco-traditional-publishing business had some bad news for another writer in the group. The other writer has written and published several novels both in trade paper back and e-book. The bad news is someone is selling print on demand copies of his books and he wasn’t aware of it or getting any money for the books sold. Seems it common for people to scrape e-books off the net and offer them for sell. They sell the books through large used book web sites but not Amazon. Self published authors and other small authors would not expect to find their books on used book web sites so they never check. One site we were shown claims the books (taken from other authors) were printed in the USA. The books from the dealer using print on demand were selling for less than the author sold them for or the price on the book jacket.
Are you a small book author that has e-books or know someone who is, then check the used book web sites and see if this is happening to you or people you know.
Write on. Professor Voltage.