CoreLogic capture their road centrelines from a number of different sources. While the LINZ centreline is one of these sources, the centrelines are mainly derived from aerial imagery.
When CoreLogic get new imagery, they will update centrelines in those areas to match the new imagery. For newly completed road projects/subdivisions, they will use survey plans to capture centrelines under construction.
CoreLogic are also linked into local council updates and are able to ensure any disparity between their centreline and a councils is checked and updated accordingly.