Various fields create mutli-value properties (TwinColum etc).
So there is the need to be able to create mutli-value property also over the area's auto creation.

Here we run into a bug:
For creating a multi-value property one needs to pass a List into the property creation.
But when defining a List in yaml, it is provided as a HashMap (LinkedHashMap) and not as a List.

So the code expects that a sub-strucutre of node should be created -> HashMaps are used for defining sub-node strucutres.

Here form here info.magnolia.rendering.generator.CopyGenerator.createNode(Node, Map<String, Object>):

                    // a sub content
                    if (property.getValue() instanceof HashMap) {
                        Map<String, Object> map = new HashMap<String, Object>();
                        map.put(propertyName, value);
                        createNode(newNode, map);
                    }
                    else {
                        PropertyUtil.setProperty(newNode, propertyName, value);
                    }

The code will go into "if" and not "else" as a HashMap is returned.

Problem:
Defining in Yaml such Lists will be retruned as HAshMap:

food:
    - Sandwich
    - Pizza
    - Burrito
    - Chocolate cake

Also this type of List:

drinks: [coke, beer, water, milk]