Nick Imrie > Status Update

So, I'm experimenting with the free month of kindle unlimited (opinion so far: not worth paying for). I've now read 2 KU books that have weirdly similar reviews on GR:

Quick header to say this book is great!
Short vague paragraph about how good the book is, could've been written by GTP-2.

What's going on? I don't want to accuse KU authors of paying for reviews? Are they all cross-posted from somewhere?