All you need to work in Canada is a SIN number. A PR card is just a travel document (a passport for Permenent residents). There have been reports of employers insisting on a valid PR card, but there is no legislation requiring it. If you e been away a while, your SIN number may need reactivating. Service Canada can do that and there is no connection to RO.
CBSA does checks randomly. There doesn’t seem to be any rhyme or reason to it. Some people without valid PR cards breeze through and others with a valid card get the third degree. All depends on the officer on that specific day. Even if you don’t meet RO, and even if you are reported for breach, you still have the right to enter Canada. The only exception being serious criminality and the like.
CBSA does checks randomly. There doesn’t seem to be any rhyme or reason to it. Some people without valid PR cards breeze through and others with a valid card get the third degree. All depends on the officer on that specific day. Even if you don’t meet RO, and even if you are reported for breach, you still have the right to enter Canada. The only exception being serious criminality and the like.