Sync does not pull settings when new devices are added

When adding a new device to the sync chain, existing settings are not synced.

Steps to reproduce:

  1. Add a new Windows installation to an existing sync chain
  2. Turn on Settings > Sync > Manage your synced devices > Sync Settings > Customise sync > Settings

Expected result:
When adding a new device to the sync chain, settings should be pulled from the server and override defaults to match other devices in the sync chain.

Actual result:
The steps above have no effect. Existing settings are not pulled onto the new device, and must be entered manually.