yes this will be a problem. The issue date needs to be after you left. And the duration can be from the when you turned 18 till date or last exit date.I was going through my docs and noticed that my PCC issuance date is 26-12-2017 but i left the country on 30th December 2017.
The certificate says that it is valid for 180 days from the date of issuance.
Will this be a problem?