Hey @seunounaiteu1! Welcome to the forums!
It looks like ghosting- could be caused by many things. I DO advise you to cook and export- it may not be there in an exported game program! Other than that usually it has to do with Lumen, and you can go into the project settings and turn that off. However, I’m not sure why you are asking why it “Suddenly does this”? Suddenly since when? Could it be that there was a new driver release for your graphics card, and that caused it? That tends to happen pretty regularly then there’s a fix released shortly after, so check after that, too! 