That beef sure exists and its present amongst some prominent Cape Town crews, i don't really wanna elaborate on this but i shall give one particular incident i remember well.
I've been to a gig once, where a member of one of the prominet cape town hip hop crews, while performing on stage went on to insite the crowd (and i choose the word carefully because the were cats from Jozi i know there) . He said one of their memberes, who was currently in Jozi, was of the opininion that Jozi is wack, that it was only liquor and drugs at their gigs, needless to say i was very dismayed by such statements as a son raised on Jozi HipHop. The gig was in pigs and swizzle. I don't wanna mention any names but if you were there, you'd obviously recall this particular incident.