Glitch/bug in Front End Development Libraries - React

To whom it may concern.
In the “Create a Controlled Input”( and in the previous)task, my code gets “TypeError: can’t access property “value”, event.target is null”, and preview isn’t working, yet my code passes when I run the tests, and submit.

We can’t reproduce without code!

If I remember correctly, instead of:
handleChange(event) {
this.setState({
input: event.target.value
});
}
I had something like:
handleChange(event) {
this.setState( input => {
input: event.target.value
});
}
But it still passed.