Whenever I had a tricky question, I always called the CIC call centre a few times, to speak to different agents and compare answers.
You may have misunderstood this agent. Since you have to send photocopies of your travel documents, even expired ones that you've renewed within the previous 4 to 6 years (depending upon when you apply), perhaps what s/he meant was that you should also send a photocopy of your expired PR card along with a photocopy of your current PR card, just as you have to send photocopies of expired and current passports.
But I would ask another agent, and see if you get that same answer.