Unity light creates rare blue light on sky-CodePudding

I'm doing a Unity project where I basically have a Directional Light rotating around the map, starting on 0 to 360 degrees.

However, when it gets dark = rotation from 100 to 120 degrees I get this strange blue light coming from the sky, does anybody have any idea on how to avoid this blue thing appearing?

Click 50mm Zoom to find it in the project view and see its detailed properties in the Inspector. As shown below.

Click on the elements, you can find that it has 19 elements, expand each element, and find that the color of one element is blue. As shown below:

That's it. Set the size to 0 and the problem is solved. Thank you, hope it helps you