Expected behavior when document requests a non-existent parameter?

[DamianMehers]

The APL returned to render a shopping list includes:

            "parameters": [
                "listItemDataSource",
                "listTemplateData",
                "keywordRecommendationTemplateData",
                "starterListData",
                "notificationData"
            ],

However there is no "notificationData" data source supplied:

My app (Voice in a Can) stopped rendering shopping lists as a result (I render APL as SwiftUI using the -core-library). I've looked into the example AplClient code and see that it passes "{}" when a parameter is not supplied (I treated it as an error and bailed)

Is this expected behavior? If so perhaps it could be documented.

Thanks,

Damian