apparently conjoined duplicate characters

[pixelp-chris]

When I make edits to many of my characters (both PCs and NPCs), I have to save my changes twice to have them stick reliably. It seems like there's a duplicate of the data for the character, and each edit/save alternates between the two.

Example: Barbarian Jim is level 3.

1. I click edit and change his level to 4. I click save.
2. I click edit again, and it still says 3. I change it to 5 and click save.
3. I click edit, where it shows 4, and just click save.
4. I click edit, it now says 5.

This isn't limited to numbers.

I can put Jim in a folder called "Illiterate PCs", and now he'll appear twice. Once in Illiterate PCs, and once wherever he started.
Jim learns to read and becomes the more refined "James", but he'll appear as both "Jim" and "James".

In these cases when the name/folder makes the duplication apparent, if I try to delete one of the two, it deletes both.

It's notable that when I do something like a Jim/James switch and search through the Local Storage using Chrome's developer tools, only the most recent edit shows up, and that's pretty reliably the inverse of what will happen when I edit Jim or James.

Example: I just have Jim.

1. I edit, change name to James, and save.
2. I see both Jim and James on character list. Previews show Jim and James. Local storage shows James.
3. I edit Jim. It shows Jim. I cancel.
4. I edit James. It shows Jim. I cancel.
5. I edit James. It shows Jim. I change name to Jill. I save.
6. I see Jill and Jim on list. Previews show Jill and Jim respectively. Local storage shows Jill.
7. I edit Jill. It shows James. I cancel.
8. I edit James. It shows James. I cancel.

Rinse and repeat. Local storage will reflect the most recent save. Edit screen will show the other one, regardless of which one you clicked edit for.

It's also notable that this doesn't happen with newly created characters. These are from my PCs and long-standing NPCs who've been in the system for at least two months.

Potentially Relevant Background

I'm an Epic Initiative patron and have logged in.
I have my PCs in folders, though it seems to have the same effect when they're not.
I have used account sync.
I almost always access from one machine, but I have used another in the past.