Hello BlueEagle,
We actually have a tutorial that shows you how to set up time of day via blueprints. There is a section within the tutorial that mentions what to do if your sun is showing through the ground. Take a look at the tutorial for your solution, but in short you need to disable the sun when it reaches a certain point below the horizon line.
Time of Day Tutorial
This was taken directly from the tutorial’s troubleshooting part.
Let me know if this tutorial helped you fix the issue, or if you need more assistance.
Cheers,