This is happening to me as well. I had this setup ages ago and I thought it was working.
I have a newsletter block setup with Google Drive for people to request a brochure. But I can't be sure if they are receiving a notification or not. But the problem is, even if they chose not to subscribe, I am not being made aware that they requested a brochure.
Whilst doing some tests, I noticed that Google Drive is adding the new email addresses to the list, but I am not being notified.
It's embarrassing to admit that there haven't been many requests, but there might have been and I would have not been aware.
At least I know about this now, but I really could do with knowing when someone requests a brochure whether they chose to subscribe or not.
Thanks, Mark.