Just an FYI - If you get a PPR email asking you to submit passports for visa stamping (when you're in the U.S) to CPC Ottawa / any VO in Canada, do not risk it. Respond to the email contact provided in the email and request to have your revised passport instructions (If you're an Indian citizen, provide a reason that as per India passport law, you're not supposed to send your passport outside your country of residence by mail. If you are a citizen of any other country, you can cite a reason that, as you're living in the U.S, it would be convenient for you to submit passports within the U.S as that would be the nearest location for you) to be issued to the nearest Canadian consulate / VFS where you're living in the U.S. They usually respond in one or two business days.
Once they issued the revised PPR instructions again, go ahead and send to that location within the U.S. I did this way and it worked perfectly fine. I got everything done and my passports back in a week I suppose. This is a safe method instead of risking to send your passport internationally.