The way pipe ends are currently calculated results in odd display issues for vertical pipes in profile view:
- There are odd angled/chamfered lines near the connection to the structure/fitting
- The pipe diameters skews more and more the closer the bend angle gets to 90 deg (fully vertical).
This issue affects pressure networks more often since connections to gravity structures like manholes are almost always vertical. But this issue can affect both pipe and pressure networks.

Current Support article: Pipes are displayed as lines in a profile view in Civil 3D