At zoom level 12 and lower, motorway links are not rendered in Wikimedia maps. Compare, for example:
- https://maps.wikimedia.org/#12/36.1893/-86.7595
- http://www.openstreetmap.org/#map=12/36.1893/-86.7595
Screenshot with missing motorway links circled:
This probably just needs a CartoCSS change to make sure it gets rendered at lower zooms.