JS output not quite right

On website I get this for hearthstone tester:

```json
{
"f0": {
"f1": [],
"f9": [],
"f5": []
}
}
```

with mapping I can get more fields, but this should work out of the box.

In my tests, I get a much larger JSON object with this code:

```js
console.log(JSON.stringify(appTree.toJS(), null, 2))
```

but `tree` gives me similar results, so I think it's not traversing into `1.2.4` correctly.

Start with the website output path and compare its tree handling with the reported appTree.toJS() result. Trace why tree does not traverse into 1.2.4, using the Hearthstone tester input, and confirm that the default output includes the larger set of fields without requiring a mapping.

Written by the indexing model from the issue text.