Unclear method for default boolean values in additional fields

additionalFields: {
      onboardingComplete: {
        type: "boolean",
        required: true,
        input: false,
        default: false //this fails
        defaultValue: false, //as well as this
      },
    },

additionalFields: {
      onboardingComplete: {
        type: "boolean",
        required: true,
        input: false,
        defaultValue: () => false,
      },
    },