Not enough info given. How long installed? How did it just show up?Is it two different colors? Some thoughts. If it is the same color which I am guessing it is. It looks like the carpet is running two different directions. That is semi common I would say going from a hallway to a room with a door. It does look like two different colors of carpet. if so, of course you'll see the seam. It appears that some shearing is needed at the seam (Fuzzing a little at the seam)Something like this doesn't normally just show up overnight.Please respond with some answers so that we can give you more absolute resolution.