Unable to save design settings of local Ghost install when offline?

Issue Summary

Perhaps related:

Steps to Reproduce

  1. Start local ghost install when offline
  2. Try to change and save design and theme settings

Setup information

Ghost Version
5.101.6

Node.js Version
v20.13.1

How did you install Ghost?
With ghost CLI

Provide details of your host & operating system
Local development install on Linux Mint.

Database type
SQLite 3

Browser & OS version
Firefox 133 on Linux Mint Wilma

Relevant log / error output
Nothing immediately jumps out at me in the console or logs.