High TTFB on using cloudfront that access to an image URL compare acess image in S3

I have no idea why the TTFB is so high when using cloudfront to access the image based on url compare to using cloudfront access the image from s3 bucket. FYI, the path of k/300/ is just for resizing the image from the url after the 300/

Below are the two image with two different link.

https://d2m21v07ktfjkm.cloudfront.net/k/300/https://cdn-doublewootenterp.netdna-ssl.com/content/images/thumbs/0079731_davinua-blush_480.jpeg

cloudfront access image from url

https://d2m21v07ktfjkm.cloudfront.net/k/300/https://s3-ap-southeast-1.amazonaws.com/ootdfixproducts/products/0079731_davinua-blush_480.jpg

cloudfront access image from s3 bucket url

Anyone know how to reduce the TTFB time when cloudfront access the image from url not from s3 bucket?