I am posting this on behalf of Jasmine Slaga from PCData.
They brought to my attention that when bulk uploading proofs, if the owner is changed on the "New Proof" page while setting up the workflow and the like, the new owner will receive a separate message for each individual proof in that upload.
Currently if a user is on the workflow of proofs bulk uploaded and it is set to "Notify Recipients" it will thread the links for each proof into one email. It would be great to see this functionality carry over into similar instances like changes of ownership, or at least the option to turn this notification off to cut back on the amount of notifications a user receives.
-Chance