I believe both A and B are at work; it's probably a direct copy of the input buffer without metadata making B likely impossible, if it were trying at all, which I'll speculate isn't even a possibility.
Copying an image from one application to another should not strip image metadata. If it does that is a bug.
I’m not sure that clipboard implementations provide ancillary metadata? Nor would it be interpreted given the wild-west application development model where application developers are the folks who would need to implement support?
It is definitely possible to copy/paste images on the Mac while preserving image metadata. That behavior should be the default. If this is broken when copying between two Apple-provided applications then that is definitely a bug.