React, form(method="POST"), why does it add parameters to url after submit?

Question

React

...
   handleSubmit(event) {
        event.preventDefault();
        event.stopPropagation();

        const email = this.refs.email.value;
        const password = this.refs.password.value;
        const remember_me = this.refs.remember_me.value;

        return this.props.onSubmitLoginForm({email, password, remember_me}) && false;
    },
    render() {
        return (
                    <form onSubmit={this.handleSubmit} action="#" method="post">
                            <input type='email' name='email' ref='email' placeholder='Email'/>
                            <input type='password' name='password' ref='password' autoComplete='off' placeholder='Password'/>
                            <input type='checkbox' name='remember_me' ref='remember_me'/>
                           
                            <button type='submit'>log in</button>
                    </form>
     )}

From time to time, it adds the login password parameters in the yurl after submitting the form, an error happens occasionally (I couldn’t catch it, but the tester also complained)
...blabla.com?email=blabla&password=111111
What could be the trouble and where to dig?