Preview Stopped Highlighting Halfway Through Document

Hello Support,

I am working with a 63-page chapter of a book in Preview. I was using the highlight, text box, and notes features to track and take notes. Partway through working with the document (with no issues), the highlighter started "jumping" when I would start highlighting a word. All of a sudden the entire page above my curser was highlighted. My workaround was just...patience. Now, all of a sudden, I cannot delete nor create any more highlighted text. The button simply does nothing.

It doesn't have to do with the type of document, because nothing about it has changed from the top (where I had no issues) to the place I am now (where highlight has ceased to function). This all happened in the course of one session, as well. No re-starting or closing any windows.

I would appreciate your help!