Losing tags when changing book outline settings?

I noticed that someone had linked parts 2 and 3 of "The Manumission Game" under part 1, instead of all three parts under an independent title page. I find that confusing when I see it on other stories -- it tends to look, in some contexts, as though the story is long abandoned with just one chapter -- so I tried to add a new title page with ++Organizer, and then link the three existing chapters to that title page. Chapter 3 looks fine, but chapters 1 and 2 have lost all their genre/trope tags (like Novella, Transgender, Magic, etc.).

Also, even though parts 1 and 2 are under the title page, they *also* show up as separate items in the list of my stories in the right-hand sidebar (along with the title page). Why is that? Is there something I can do to fix it, or is it something only an admin can fix?

It may be relevant that parts 1 and 2 were posted before the downtime, and part 3 after the site came back up. But I think they still had their tags after the site maintenance and before I changed their outline settings.