Can anyone identify what could have happened?

More information please. Is it a new car or used? Where was the car located on the car carrier? I need a couple pictures of the entire car to get a better idea.

 

With the new information you provided I will explain to you a few reasons why I don’t think it happened on the carhauler.
1.The vast majority of new car check in people would have noticed this area of exception when checking the unit in.
2. If the new car check in person missed it, the PDI (clean up people) would have noticed it and would have buffed it out.
3. This car had been through at least one car wash before you noticed the damage nearly a year ago.
I am not saying with certainty this damage occurred after it left the dealer, but it is entirely possible. I also understand your frustration, because I am extremely anal about keeping my vehicle clean and scuff free. However if you didn’t notice it when you bought it and didn’t notice it for 13 days afterwards its not that bad. My advice is you go on Amazon and get some of this 3M and rub on it for a few minutes until it very likely comes off. I have been on the other side of the coin where I was blamed for and paid for damage that did not occur on my rig and the damage was not on the vehicle when I delivered it. However I night dropped the units I had to pay for and the dealer passed damages I didn’t do back to me. I won’t be placing any responsibility on a carhauler that delivered this nearly a year ago because it is entirely possible it didn’t have this damage on it when the carhauler left the dealership. Typically a long scuff like this that does occur on a carhauler will be front to back from a tree branch not side to side. A side to side damage would be from a car too close to the deck over top of it and will result in body damage. If you were a dealer who found this damage 5 minutes after the carhauler left and it hadn’t been run through the dealers car wash, I would say the damage was on the vehicle when the carhauler left it.
From a legal and also moral standpoint regardless of when the damage was done once the dealer inspects it and signs the carhaulers delivery receipt as clear and no damage the buck stops there. The same as when you the customer looked the vehicle over, signed the sales receipt to buy it and then drove it home only to find damage 13 days later, the buck stops with you. I am not picking on you, but I am a realist and stuff occasionally does happen that we may not be aware of when it happens.

 

I don’t dispute the damage being there. The problem is nobody knows when it got there or who put it there. If you sold this car to someone and didn’t know or think it had damage on it and then 13 days later they called you and told you it had damage, would you being willing to accept responsibility and pay for this damage?

 

Once again the front to back damage could be similar to a tree branch. The side to side would have body damage if it were done from rubbing on a carhauler while riding down the road. Either way it’s irrelevant because it was clearly not hidden damage. While it is unfortunate it is still nobody’s responsibility but yours after you have possession of the vehicle. How does anyone know what all that car has seen in those 13 days?

 

I really am sorry this has happened to you, but a good independent body man can fix this for less than $1,000. I keep my new vehicles for years and years and can appreciate you wanting it to be perfect because I do with mine also.

 

As @Banker pointed out, transverse damage from transport tends to be dents that are deeper in the center of the roof from a crossmember. This damage was done by something draped across the roof, and I can't picture why a chain would be transverse across there, so my best guess is that was a dirty pressure washer hose that sat there and vibrated with the hose draped across the roof of the car.