Hi ,
Its a strange and rare incident and I dont want to go into the details and discuss its reasons.
As its not a common situation so anyone cannot give you correct information,though in my view you are already PR of Canada,but without a PR card appication so your best bet should be to call CIC and discuss this situation with their representative and I hope they ll be able to give you exact and correct info.
Also do visit your e-cas status ad enter your Immigration File# ,it will also show what CIC has entered in its records about your landing.Usually it shows the date and port of landing and mentions that applicant XXXX became PR of Canada on so n so date .
If CIC suggests you that you can apply for PR card when next time you visit Canada,and your e-cas status also shows that you have become PR of Canada ,then nothing to worry ,and apply for PR card at your next visit .
Hope it helps!