You PCC has to be valid at the time of your AOR, that's it!!!
Valid, for IRCC, means that it must have been issued after you're last in that country or within the last 6 months if you're still in that country. So suppose you came to Brasil on Aug 2002 and got a PCC last year (Jan 2016) it's still valid for IRCC's purposes (even thought the Brazilian PCC says it's only valid for 90 days).