@YULIA-2016 Please add me, thanks! Indeed, it looks like CIC has started processing the applications that were sent on the first few days after the invitation. Also, the "intern" theory made sense as I couldn't see E-case at all, even in this morning, until application was finally able to link on MyCIC. Best of luck to everyone.
Username : DC1018
Sponsored : Mother-in-law
Parents Country Of Citizenship : China
Province : BC
Invitation Received: Apr 24, 2019
Application sent to IRCC: Apr 24, 2019
Application received: Apr 29, 2019
E-case status for sponsor: Application received on Apr 29, 2019
AOR: May 31, 2019
By the way, I was actually able to link the application and retrieved the FN on MyCIC by using applicant's name, DOB, Passport and # of family number (minus children) a few hours prior to receiving the actual AOR email. If you sent your application around the end of April but haven't received the AOR, you can try to link your application online first. Hope this information helps.