There are certain speculations going on as to how and who are getting AOR, apparently one guy from sept 2019 on the FB page posted that he called IRCC and the agent explained to him that the process of sending AOR has changed since the officers are working from home. Some officers send AOR upon checking the completeness and to send the AOR they have to book and appointment at the office to come there and send AOR, while some officers will mAke sure that all steps are done like background, criminality and security etc is done and then will send the AOR. The final step will only be medicals.
Thats why some are getting it early while some from august 2019 are still left to get their AORs. I am not 100% sure how much is the reality, just hoping that the ones who are left out should get it soon