Weird Shadows on Union

[cwd30 (seawead30)]

I am making a union right now, it’s a very simple union so I don’t see any problems with “complexity” and the amount of triangles it has, but there’s these weird reddish shadows that pop up after I union it and go away once I separate it. The shadows stay when you test the game too, and looks very weird. Anybody know how to fix this?

Here is a GIF of me unioning it, and the shadows are visible in the GIF too.
https://gyazo.com/1b0d602650a5bb3b2710dfce65e8ee8a

In case you can’t view the GIF, here is a picture of the shadows:

And no, there is nothing above the union that would be causing these shadows.

[Khronikus]

I had this same problem on a windmill I made, but there’s a simple way to fix it:
Turn off ‘Cast Shadows’

[cwd30 (seawead30)]

How did I not think of that, haha! Thank you very much!