path.split is not a function

Describe the bug Follow the initial Get Started documentation, install on a new Create Next App. Adding an input with ref={register} produces blocking error.

To Reproduce Steps to reproduce the behavior:

1. Create Next App
2. npm install react-hook-form
3. Copy example block
4. Unhandled Runtime Error / TypeError: path.split is not a function

Codesandbox link (Required) Occurs on default CodeSandbox: https://codesandbox.io/s/react-hook-form-defaultvalues-v6-09b8g

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• “react-hook-form”: “^7.0.0”
• OS: macOS latest
• Browser: All

Additional context

import { useForm } from "react-hook-form";

function Form() {
  const { register } = useForm();

  return (
    <div>
      <h2>Form</h2>
      <input name="firstName" ref={register} />
    </div>
  );
}

export default Form;