When I use the web-based capture, the script is capturing too many notes. It will capture all the notes from the book that I am "at" in Safari (https://kindle.amazon.com/your_highlights_and_notes/[ASIN]) but will also capture a handful of notes from another book.

I've replicated this problem consistently with a number of books. Each time, the unwanted clippings come from the same book. It appears like the script captures all the clippings from that book with locations that are higher than the last location clipped from the intended book.