I’m not an expert on tree disease either, especially in North Carolina … but my assumption is that sap ‘snuck past’ the cut before the buds below it could form branches and give it a place to go… I suspect the dark color is due to mold or simply decay of the escaped ‘sap.’

If the rest of the tree appears healthy, which from the photos, it does, I wouldn’t worry. If an entire branch (other than the small darkened shoot) begins to show signs of demise, I’d remove ‘that branch’ from the tree as not to allow pathogens to spread. But from what I can see, it looks fine.

If the shoots around the cut continue to show healthy growth - that should seal and heal the oozing wound with no problem. …and, I was waiting for ‘an expert’ to respond as well