It turns out the ebook click farming scam is getting more common and the farmers are disguising their practices by roping in legitimate books from innocent midlisters along with the ones they're paid to boost.
https://the-active-voice.com/2016/06...t-think-again/
http://www.thepassivevoice.com/2016/...rawny-authors/
As I pointed out above, the practice hurts everyone; readers, authors, and yes, Amazon.
Since it is relatively new in the ebook space Amazon seems to be fumbling around for a handle on the problem.
Probably going to get uglier before it gets better.