I’m Kevin, one of the devs at Redux. I’d be happy to take a look at your situation more closely if I could get you to hope on over to our github page and submit your issue via our issue tracker https://github.com/ReduxFramework/redux-framework. Please be sure to include the version of Redux you are using (important as we might have a newer version) and a sample of your config, specifically the section you are attempting to use here.
Thanks!