In a “large world” map, it’s possible that the camera scroll limit doesn’t reach one of the map edges - i.e. the camera will stop scrolling but there’s still more land to view and not reached the seacoast yet. You can still attempt to build beyond the area the camera won’t scroll to by zooming out, but this doesn’t always work and sometimes the limit is quite far inland.
Increasing the world coordinates for camera scrolling should fix this, I think? Love the recent update, the colonists look a lot nicer