firefox copy-paste bug repro

HTML

<div id="app"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

class Repro extends React.Component {
  constructor(props) {
    super(props)
    this.state = { files: [] }
  }
  
  componentDidMount() {
    window.document.addEventListener("paste", (ev) => {
      const file = Array.from(ev.clipboardData.items)
        .filter((item) => item.type.indexOf("image") > -1)
        .map((item) => item.getAsFile())
        .filter((item) => !!item)[0];

      if (file) {
        return this.setState((state, props) => ({ files: [...this.state.files, file] }));
      }
    });
  }
  
  render() {
    return (<div>
    	{this.state.files.map(file => {
      	const objectURL = URL.createObjectURL(file);
      
      	return <img width="100" height="100" src={objectURL} />;
      })}
    </div>)
  }
}

ReactDOM.render(<Repro />, document.querySelector("#app"))