That's very hard to know without being in an FMRI machine while reading, which I wasn't, sadly.
Just functionally, it seems reasonable that something happened before that bad feeling to trigger it, e.g. "trying to fit this with already known things, and finding it doesn't".
Just functionally, it seems reasonable that something happened before that bad feeling to trigger it, e.g. "trying to fit this with already known things, and finding it doesn't".