Just want to share some of my ideas:
If your medical shows 'you don't need a medical exam', that means your medical expires and you are waiting for the officer to extend it.
If your medical shows 'you passed the medical exam in xx month, xx day, 2019', that means your medical is extended and all you need is the final review from the officer.
Even your security check is not started, but if you are in Canada as 'in-land' PR applicant, your security might be finished within a day or so.
Of course, all these are my guesses but seem pretty reasonable explanation. So Jan applicant, that email is just at the corner now.