Decreasing range of box light on Mac creates a jagged line in the light's edge on a flat surface.
Tested on Mac and Windows, but only occurs on Mac.

1.Create new HDRP Template Project.
2.Create a new scene and open it.
3.Click on Directional Light in the hierarchy to open in inspector. Change the Directional Light type to ‘Spot’.
4.Change the light shape to ‘Box’.
5.Underneath the light shape dropdown, set ‘Size X’ and ‘Size Y’ to 10.
5.Set Position of the light to (0, 2, 0) and Rotation to (20 0, 0).
6.Create a Plane in scene. (GameObject -> 3D Object -> Plane). Ensure it is at position (0, 0, 0).
7.Increase and decrease the range of the light.

Expected result: as the range is decreased, the edge of the light hitting the plane should be a straight line.
Actual result: The edge of the light is jagged and much closer to a zigzag than a straight line.

Video of this bug attached to the case.
Note that rotating yourself in scene changes the appearance of the jagged line.

Tested and reproducible in 2019.3.0a12 with package version 7.0.1, 2019.1.13f1 with package version 5.7.2 and 2018.1.9f2 with package version 1.1.4.