There's a reason why it is so cheap:
Group regulated crappy unit... just terrible.
Speaking of the tier list, even though there are no reviews for some of the units it's still a great guide. Depending on the topology, components selection and so on these PSUs can still be classified... sure a review will be more comprehensive, but it still won't test reliability. Just looking at some internal shots of the units gives you a good idea about what you should expect.
Also, why are you asking about such a crap PSU when you supposedly bought a Seasonic Core GX?... I assure you that going by that tier list you'll be getting a much better unit compared to what you chose so far.