TTMSFNCTileList.Items not recognized by TMSFNCPersistence.FromJSON in JavaScript

FNC TMS FNC Core
6

According to this code

collection.Clear();
    for(let jsonItem of AJsonObj[ACollectionName]) {
        item = collection.Add();
        pas["WEBLib.TMSFNCTypes"].TTMSFNCObjectHelper.FromJSON.call(item,JSON.stringify(jsonItem));
    }

You are trying to load JSON into the collection item, which collection is this? Is this the tile list collection? Note that the JSON is the full component JSON meaning it should be loaded directly at tile-list root level (TMSFNCTileList1.JSON). If you only want to persist the collection, use TMSFNCTileList1.Items.JSON