Under certain extreme circumstances Unity will render aliased shadows. It probably affects very few users.

Florent asked me to create this bug report because it might be helpful in his planned work on shadow filtering.

In the attached scene you can see an extreme example. Notice that:
- directional light is at a very shallow angle
- directional light is extremely bright (intensity 8)
- no shadow cascades
- shadow type set to hard
- using linear color space (as defined in Edit > Project settings > Player)

Play with the above mentioned settings to see how it affects the severity of the aliasing.