Item names disappeared on the timeline and no longer show up in publish or preview

Update: I was able to fix it, kind of. It's showing now in Preview and Publish, which I guess is fine but it's still doing weird things.

I'd attach this to the support ticket but I can't find it.

Case Number: 03426491
Reference ID: ref:_00D30Txo._5004y29qdGH:ref

I redownloaded the problem numbers' icons, renamed, resized and replaced them. Then I ungrouped the group they were in, deleted the problem number, put the new number in the group and regrouped. It created new groups starting at Group 12, which I renamed to the correct numbers. BUT! It didn't keep the new number on the timeline on the new ones, except 11. Puzzling, for sure. This didn't impact the publishing, so it's not a big deal but definitely quirky, for sure.

Expanded view

I don't know if this is a factor - it shouldn't be, but when I've been saving I get a notification that I can't save because it's being used elsewhere and might have been modified by another user. I'm working using the client's login here, have my own personal account, and have used a login for a college I did work for as well, all on this laptop. Maybe there's a cookie or something that's causing this confusion.