pthumb strips Adobe Content credentials from cached images

[valokammi]

I've added Adobe Content credentials to originals that are downloaded to media source.
All photos in pages are rendered and cached by pthumb.
When I download cached image from page and try to detect Adobe Content credentials it shows that Adobe Content credentials are missing. Page show correct variants of images because Adobe Content credentials are stored files and cloud.
To test I downloaded photo from media source and tested Adobe Content credentials and they are correct.