This article from the CO about the pending runoff between Pendergraph and Pittenger was completely predictable.
Some voters in NC ninth runoff not happy with candidates - CharlotteObserver.com
See below posts about the causes of same from before the first primary...
No Rest for the Wicked...More Negative Adds in NC-09 Posted 5/9
Do Candidates Matter or Just Money? Answer Posted 5/8
Pendergraph Electability Takes a Hit Posted 5/4
Do Candidates Matter or Just Money? Posted 5/3
NC9 Congressional: The Case for Killian. Posted 4/26