There seems to be a lot of inconsistent practices across the NCDOT divisions.
Sounds about right. About two years ago, I emailed NCDOT and asked them if there was any timetable for signing the Goldsboro Bypass as I-42. I got a response from the Division 4 PE at the time, Matt Clarke, who basically said that all of US-70 would need upgraded before I-42 could be signed.
This was after NCDOT's Chief Engineer, Tim Little, told the US-70 Corridor Commission that FHWA had given it's approval to slap I-42 shields on the Goldsboro Bypass. Go figure. ¯\_(ツ)_/¯