on The Blood Red Pencil:
In addition to reviews, KDP and readers can also flag your book for typos and “quality issues.” Kindle is now cracking down on poor quality ebooks, which can be both a gift and a curse. It can identify plagiarists, scammers, and cut and paste thieves. But I’ve read posts on forums where writers complain that readers have unfairly flagged their books. The concern, of course, is trolls targeting authors with this new tool.
Whatever the cause, if you find your book flagged you have the opportunity to fix it and to appeal.