@Override
            public void entry(int idx, Inspector inspector) {
                switch (inspector.type()) {
                    case STRING -> array.append(inspector.asString());
                    case OBJECT -> decodeObject(slime, array.append(), inspector);
                }
            }
Try and verify that index mode is possible.
config/src/main/java/com/yahoo/vespa/config/ConfigPayloadBuilder.java