I had a similar thing happen to me just today. A friend of mine had finished a book in a series. I have read the series but it was almost 10 years ago, and I needed a refresher with spoilers, so I went looking.

Well, some redditor had posted a comparison of a much later book in the series, and drawn all sorts of parallels and foreshadowing and references between this quite early book I was looking for and the much later one. It was an interesting post so it had been very popular.

The AI summary completely confused the two books because of this single reddit post, so the summary I got was hopelessly poisoned with plot points and characters that wouldn't show up until nearly the conclusion. It simply couldn't tell which book was which. It wasn't quite as ridiculous as having, say, Anakin Skywalker face Kylo Ren in a lightsaber duel, but it was definitely along those same lines of confusion.

Fortunately, I finished the later book recently enough to remember it, but it was like reading a fever dream.