Following your lead, I called IRCC (my ceremony was on April 24th - Scarborough - and I did receive the email invitation).
She said that they don't have a date yet for me, and they're in the process of rescheduling me for a date "very soon". When I told her, I have travel plans next month and if she could be a bit more clear on what that time frame might be like, she said "don't worry, you're very high priority" (whatever that means

) and that "you should be receiving another email invitation very shortly, just wait for it.
Not sure what to make of this.