If you have multiple values in type, you can use these syntaxes:
type: [principal, bad]
type:
- principal
- bad
type: principal, bad ins’t the right syntax for multiple values.
Besides that, for type: [principal, bad], types returns a list of two values: principal AND bad. In this case type = "principal" isn’t TRUE (because “type” has also "bad).
When multiple values you can use contains(key, "value"). In you case:
LIST FROM #character
WHERE contains(type, "principal")