Activation Lock email vs still showing entirely offline in Find My for stolen device

I got an email with "activation lock is requesting your password on" an iPad that was stolen months ago. I know through verifying it actually came from Apple and reading other people's questions about the same thing that this means someone's trying to get into my iPad and it didn't work.

But what I'm confused about is how the iPad was able to inform the Apple servers about a failed activation, while still showing as entirely offline with Find My. I had a sliver of hope about finding it or at least getting information when I first saw the email, but logging into Find My it's just as offline as it's been since the day it was stolen. Why is that? How does that work?