Purple ambient while there is no change in the lightning settings..?

I've added a few plugins to make the scenery and all look more realistic and smoother, but for some reason I got this purple lightning shown on the terrain (or basically every part) in my place. I checked both the Ambient and OutdoorAmbient and they're both set as default. Does anyone know why this happens and how I can fix it?

(Added a picture of it, but I hope it works. First time posting a question with a picture.)