Hi Nooruluda,
I concur with Ashuindian. Although the document checklist does suggest that those can be submitted later, it better to include in your initial submission to avoid rejection (different visa office operate differently and reject on various grounds). That being said, it is recommended you provide them with a letter of explanation indicating you are working on obtaining your PCC and in due course you will submit them soon as they are available. Considering you just received an additional documentation request for the same, go ahead and submit them asap. I dont see any issues with your application as they have already processed it through. Good luck!