Working on a catalog, all tables, everything was fine, generated my TOC and no surprises. Had to add a section on to the back, and after I did that and refreshed the TOC, it DOES show the new stuff, but suddenly now a lot of the entries before that have gone missing. I've checked and all my paragraph styles are intact and fine - even tried applying basic paragraph to the entries that were missing in the TOC and reapplying my style that the TOC is supposed to find, but still no luck, it just will NOT generate these certain entries.
What are possible reasons for missing entries in a TOC? I feel like I've looked at everything. Weirdest if all is the fact that these entries WERE showing up, and then suddenly they aren't, and I can't see how any of the changes I made in the meantime should be causing this.