Yes that is AOR. And for why it is sent to sponsor email, you can see the reason on the letter itself "this is to confirm your application to SPONSOR".
I have received my BVL today too for my Open work permit. I sent it April 9, 2024 and the next update was BVL today May 1, 2024. They did not request for biometric and medical cause mine still valid. Im waiting for final decision too