Custom bang settings overwritten when bang is moved in the More menu

When I reorder my custom bangs within the More search menu, their configuration gets silently overwritten.

Steps to reproduce on desktop (Chrome on Windows 10):

Open Settings > Search > Advanced > Custom bangs.
Add a few custom bangs with distinct names and check the Shortcut Menu checkbox for all of them.
Create a custom bang X with a regex pattern and check all checkboxes except URL Encode Space to Plus (+).
Save the X bang and open its editing screen again to verify that its settings have been saved correctly.
Keep the Custom Bangs page open.
In another tab, navigate to the homepage, open Search Options > More and click Customize...
Drag the X bang up or down to a different position in the menu.
Click Back to exit the Customize mode.
Switch back to the Custom Bangs tab and reload it. The X bang has moved to the new position here as well.
Open the X bang and examine it.

Expected: the regex pattern and the checkboxes should be preserved; the URL Encode Space to Plus (+) checkbox should remain unchecked.

Actual result: the regex pattern is now empty; all checkboxes are checked, including the URL Encode Space to Plus (+) checkbox.