(Dynamically created) line object invisible until moved on z axis

I first thought this is similar to https://shapes.userecho.com/en/communities/1/topics/34-polyline-with-world-pos-points-located-at-origin-does-not-render-until-you-look-at-the-origin

but in this case UpdateMesh(true) doesn't help.

I create a line object dynamically from code that starts outside of the cameras view but runs into the view (end point is within view). And this is not drawn, until it is moved along the z axis (even the tiniest amount, + or - doesn't matter); x and y movement don't help. The problem seems to be that the lines start point lies on the plane that would be defined if you take the cameras view vector as normal vector... so in this particular example then lines have the exact same z coordinate as the camera (with the camera looking straight down (0, 0, 1)