Fields don't update state if has changed before first render

### What is the current behavior?

If we set the values on fields (using `form.change`) before the fields have initially rendered the values are not shown in the fields.

### What is the expected behavior?

The fields should render with the correct values.

### Sandbox Link

https://codesandbox.io/s/react-final-form-fields-component-fo72p?file=/index.js if rendering the `FormControls` before the fields it doesn't correctly set on initial render, if rendered afterwards it does set correctly.

### What's your environment?

"final-form": "^4.18.6"
"react-final-form": "^6.3.0"

### Other information