Checkbox always shows true in ReactJS only on production

So I have very specific issues. I have checkbox with controlled component and it works fine on local machine, but when I push code online, then everything works (check/uncheck), data are ok "0" and "1", but checkbox is always checked. Anyone knows what might be cause of problem?

http://ift.tt/2wVCSsl

Here is my code

    <input className="float-right" type="checkbox" defaultChecked={course.is_featured} onChange={this.toggleChecked.bind(this, course.id)} />