I’m going to post this here, since this seems to be where most Epic developers are active these days, and I think the Sunposition blueprint was added very much for Datasmith:
The Sunposition blueprint does not change the light intensity, which results in the bug that shadows go wonky when the sun is below the horizon.
What should happen is that the blueprint should take a reference to a directional light in the scene (and perhaps an intensity range):
And then, depending on longitude and month, tone the intensity down depending on the hour of day, and most importantly, become zero when the sun is below the horizon!
(Changing the light color should be a tickbox option too, because I’m guessing weather system marketplace assets might have something to say about that.)