This error happens when you type extremely fast. The more components you have alongside it, the more likely that this will happen.
<TextInput value={this.state.value} onChangeText={value => this.setState({ value })} />
And if you hit submit IMMEDIATELY after typing, the value won't be set and the input may just be blank.
In order for the value to actually be there, you have to wait just a little bit, then you can hit enter and the value will stay.
This is on iOS.