Does your lawyer know that or is he guessing? Is he actually a lawyer? Where is that written? Does the PPR mention the passport number to be sent?No. It's not expired.
PPR on June 15. My child's passport had only 6 month validity. So, I renewed thr passport. My lawyer said you can't send new passport in the existing PPR and I needed a new PPR
You can send in new passport and they will stamp visa on that. I have personal experience in that. My spouse's passport had expired and I had sent the new passport and IRCC had stamped it with the visa. There was no need to get a new PPR.