The phrase "discernible relationship" means being able to see or understand a clear connection or correlation between two or more things. Full definition
This point won't be shared nearly as many times as the original image, but this «church» is really a cult, with no discernible relationship to Christianity. (relevantmagazine.com)
They are, as religion reporter Amy Sullivan points out, some sort of cult with «no discernible relationship to Christianity.» (relevantmagazine.com)
Despite assiduous efforts, however, they have usually found no discernible relationship. (educationnext.org)