presets: [Bug] websocket error with CRA 4.0.1 and storybook 6

Describe the bug

After updating to storybook 6 and CRA 4 I see websocket errors in browser console and dev-server constantly disconnects.

WebSocket connection to 'ws://localhost:9000/sockjs-node' failed: Error during WebSocket handshake: Unexpected response code: 404

Steps to reproduce the behavior

1. Create empty CRA project with the latest version (4.0.1)
2. Init it with storybook
3. See error in opened browser

Expected behavior

Hot reloading is working and there are no errors.

Screenshots and/or logs

Request URL: ws://localhost:9000/sockjs-node

Environment

• OS: MacOs
• Node.js version: 12.12.0
• NPM version: 6.11.13
• Browser (if applicable): chrome