Option to customize the online store theme has vanished

[Spacehaven]

When I click on the menu item Online Store -> Themes, I only get the theme store info, nothing about my current theme, and no option to customize or open the theme editor.

Attempts to fix: I searched everywhere else, and didn't see an option to edit the theme. I also checked permissions, tried a second browser, even disabled my ad-blocker. Nothing. I checked the system status page, all green.

Does anyone know what's going on? Is anyone else experiencing this?

[Spacehaven]

Next day: It's back and working fine.