TextInput fire onContentSizeChange with wrong content height.
While you typing the text to the half of TextView width (I'm sure that the text still not reach the end of TextInput width by rendering the red background), the onContentSizeChange fire with the new height (of course bigger than the previous height). But the text still not wrap to new line, you can continue typing on the first line.

1. react-native -v: 0.47.0

Then, specify:

• Target Platform: iOS 10.3