Vertical lines not drawn if generated with lists

Something’s not working the way it seems like it should.

When I use lists to draw multiple lines (in this case, tangents around a unit circle)

I saw all but the vertical lines

But I expected all lines to appear.
Each line individually can be drawn, even as part of a list. In the attached page below, only 6 of the expected 8 lines are drawn in red, but the blue line, which draws only one line from the list, has no problem being vertical.

Here’s the link to the page, dashboard, or activity:

And here are some screenshots:

Expected (achieved by adding a tiny amount to the angle):