Change of content is not reflected when nodes or multiple fields are included in the container.

## Issue
Change of content is not reflected when nodes or multiple fields are included in the container. They are only reflected when one single plain string (without any other text around it).

## Steps to reproduce
1. Have something more than a single variable in ``, e.g. `Text: {text}`.
2. Modify the `text` variable by triggering any event.

## Expected result
Content of the node change accordingly

## Actual result
Content does not change.

## Reproduction sample
https://codesandbox.io/s/react-balance-text-bug-report-bw58v

Start with the BalanceText component and reproduce the behavior using the linked CodeSandbox sample. Trace how content updates when the container includes plain text plus a variable, or nodes and multiple fields. Done means changed values are reflected in the rendered node in each described case.

Written by the indexing model from the issue text.