"hand-drawn" shadows cast by directional light.

Godot Version

4.3 stable with C#

Question

When enabling shadows for directional light it casts them like this :

It look as if shaded by a pencil.
Spotlight shadows seem to not have this problem.
Those are the only active light sources. Although I have “WorldEnvironment” set to “Sky”.

When directional light is off, the present shadows look OK for the most part.
Please help me if you can. - I’m new to godot.

You can also point me to other posts or solutions that are already present. - I don’t have any good idea how to call this behavior, which is why I’ve found nothing similar on the internet.

Update: When I rotated the “DirectionalLight” so that it is not absolutely parallel to the game world, shadows work fine.
Do you think it’s a bug ?