CIC rejection of application is ahead of acceptance and sending AOR. Thats why June and July applicants have started receiving rejection than acceptance.Definitely. In fact, another applicant from July 2020 received a returned application due to language proof a few days ago. So they're already going through July applications too.
I guess there's a little delay between when they open and review applications and when they send AOR. It's probably like an assembly line. Applications that are complete probably move to another pile awaiting AOR while incomplete ones are sent back.