I read a book a few years ago--it was actually a TV book club selection, though I didn't know that when I bought it--so littered with inconsistencies my reading became a game of "Spot the error."
The MC's age changed repeatedly: She was seventeen, the eighteen, then seventeen, then twenty due to addition/subtraction with the original age given for her mother, which also changed from 35 to 37 to 34.
In one scene a character is described as sitting on a couch with the hems of her trousers wet from rain. At the end of that scene she stands up and smooths her skirt.
The MC is spending the night at a friend's house, and she has a thing for the friend's brother. A chapter ends with a line about how they said goodnight and she didn't see him again for several weeks. The next chapter is about how awkward it was to see him at breakfast the very next morning.
Those are the ones I can remember offhand, and I read the book five years ago, I think. There were more. There were a lot more. I'm not one to say books read like they haven't been edited or whatever, because everybody makes mistakes, but in this case I honestly seriously had to wonder if anyone had read through it before publication. Those were not small errors, they were major continuity issues.
The idea that a popular TV show actually picked it for their book club, even with the myriad mistakes, still makes me very sad. I didn't watch the show, so don't know if the problems were mentioned on it, but I somehow doubt they were.