Not sure if this is a Factorio bug or Cargo Ships, but the highlighting for the Port only shows up on the right side of the waterways.
I can still place the Ports on the left side and it does snap in to place and work as expected. But the highlighting is bugged for some reason.
Left/right highlights both directions.

Not sure if this is a Factorio bug or Cargo Ships, but the highlighting for the Port only shows up on the right side of the waterways.
I can still place the Ports on the left side and it does snap in to place and work as expected. But the highlighting is bugged for some reason.
Left/right highlights both directions.