Either I've found some weird bug, or I'm doing something wrong.
My Preflight says that "The document index needs updating." and provides a "Fix" button. However, every time I mash the button, nothing happens other than additional entries showing up in the Index Panel (but not on the page). The error remains, and the Index Panel resets itself back to one entry per after a few moments. (see screenshots attached)
If I delete the frame with the entry, the error still remains.
I have only 1 index and 1 table of contents inserted in the entire document.
Am I missing something here?