This is probably a mystery meat problem that I have encountered several times but I cannot reproduce. That is curves not showing up in some views.
Here I have views of the same set of curves. In the Top (at the top) you can see a set of points with not curve through them.
In the perspective view, there is a line visible through the points (at the top).
If I select the curve in the perspective view, it shows up in the top view.
This problem seems to go away by changing the view. I took the top view window, switched it to bottom, then back top and the line now appears.