Fastly CDN-forever cachable issue

Hi team

I am using Faslty CDN network for my application, in which having issue in thumbnail creation and upload image on it.

I am using Drupal 8 version and CDN module to setup Fastly CDN configuration, When am upload image through CDN path it's upload file inside folder /Files/image.png, but at same time image is not uploading into thumbnail folder. But am disabled CDN configuration then image is uploading on both folder /files/ and /thumbnail/.

Below is details description with image path.

1.) works: https://cdn-doamin.com/us/sites/us/files/NorbFastlyTestThree_0.jpg
Not work: https://cdn-domain.com/us/sites/us/files/styles/thumbnail/public/NorbFas...

How does Drupal validate itok?

2.) works: https://cdn-domain.com/us/sites/us/files/coperta_30.jpg
Not working: https://cdn-domaine.com/us/cdn/farfuture/7fPXsGzPQo7CUdilOBMTARjP_snit7D...

Question about "forever cachable" - How does Drupal take the "/farfuture/dhsdhsadhjsbfbdueiu/" and know how to handle that?

Thanks,