By this book, this series has started to feel "stretched".
We have a saying in Greek about this kind of thing, "to pull it by the hair", when a creator decides to keep a series/ a TV show/ etc. going, even though they don't really have the inspiration or will to do so anymore (in this case: "Eoin Colfer is pulling the Artemis Fowl series by the hair!"), so they just introduce increasingly ridiculous plot points. For a prime example of this, see JK Rowling's "The Cursed Child", which is a JOKE. Enough said.
So like I said, this series has begun to be pulled by the hair with the introduction of YET ANOTHER problem that might expose the Fae world to the humans. So many in the approximately 2 years that Artemis has known them. If fae-exposing issues arise so often, how did they deal with them before Artemis, to whom they run asking for help every time? The problem in this book wasn't even caused by him at all, unlike the previous ones.
Also: Holly quit the LEP at the end of the previous book, but is recruited at a very similar service at the beginnng of this book, so basically nothing changed even though her quiting the LEP was a big deal in the previous book.
Hey, all the AF books were written in a very simplitic, dare I say lazy writing style, but this one is the one where the plot got a bit lazy too. I'm kind of attached to the characters now, so I'll finish the series, I want to know how it ends. But let me just say that I've already started the next book and it seems even worse than this one. Sigh.