It is currently possible to set all types of valid JSON within the
`payload-preferences` collection via the REST API, but not the Local
API. For example, locales are currently saved as plain strings to the
`value` field, something that is only possible through REST. This is
because there is a custom POST handler that submits the data directly to
the db using the update operation itself, bypassing typical `json` field
validation. However, when using the Local API, it does not behave in the
same way, and throws a validation error instead. The fix is to add a
custom `validate` function to this field that attempts to parse the
value, and if it succeeds, returns true. This way both APIs behave the
same.
6a262ab809