It's just a guess. But it's a very educated guess, given that no one I know has gotten it from the Aug 2019 applicants. However, by looking at the history of applications (in the google sheet), it looks like this happens every so often: suddenly AORs take long or short. I wouldn't freak out, given that a lot of people are on the same boat. It might just be that CIC probably stops processing AORs if they've gotten a big batch.
Again, this is a guess, but if you look at the google spreadsheet, this has happened in the past:
https://docs.google.com/spreadsheets/d/11kdzo2tA_6HiILyuHtDsYtVajswDvHYTUiEFlFM1b28/edit#gid=185830120