I tested in the 99th percentile for reading comprehension all through school. I also regular miss things when I read and have to go back and realize I'm a dumbass. If my comprehension is better than 99% it's very concerning.
Going back and realizing you're a dumbass is like 99% of reading comprehension. And iterative learning in general. Assuming you know everything at first blush is absolutely how shit like this happens.