In Civil 3D 2023.2 and newer versions, civil object labels that are not entirely within a viewport do not display by default. The labels will plot, but are not shown in paper space. This is due to new labeling settings introduced in Civil 3D 2023.2. This is controlled by the AeccViewportOpt setting.

AeccViewportOpt set to ON in paper space:

Model space:

The basepoint for the highlighted label is about 500 feet further to the west.

AeccViewportOpt set to OFF in paper space: