This will fail on the last line:

ModelNode list = new ModelNode();
list.add("a");
list.add("b");
list.add("c");
List<Property> propList = list.asPropertyList();
assert propList.get(0).getName().equals("a");
assert propList.get(0).getValue().asString().equals("b");
assert propList.size() > 1;

The unmatched "c" gets dropped.

A list like this should fail in asPropertyList() with an IAE. In theory we could add a Property with name "c" and an undefined value, but since this never worked before I think we shouldn't try and support an ambiguous thing like this and should just reject it.