He does say he only checks via prescient, in the book’s time, to make sure they’re still on the golden path so he can get surprised. That is one of my favourite bits as well, he sort of gapped out for a moment. Then later we get introduced to him talking about wool gathering when Moneo’s mind wanders, that just made me ponder if that phrase was because he kept thinking about his surprise earlier in the story due to his own wool gathering. If I recall that phrase came up a few times in the series but I can’t remember if earlier or later books.

Also if you think about it, never being surprised and living thousands of years would be quite boring and humanizes him in a way that most people would not think of since he’s the worm.