Why is iBooks progress incorrect in my Siri Suggestions, and how is this fixed? In this case, Siri Suggestions implies that I have just started the book. I've actually been reading it for weeks and am on page 685/1985. Clicking the Siri Suggestion for the book brings me to the correct page. This is on iOS 9.1 (13B143).
Go to Settings>General>Spotlight Search. Turn off and on Siri Suggestions. It worked for me.