Omg it happened to me as well!!!!! I had a previous SIN number as a worker but I changed it when I got PR… received on the mail, saw the 1 and didn’t think anything about it until yesterday when I applied for a credit card and the lady at the bank asked me if I had lived or being on Nova Scotia, PEI or Newfoundland… I was so confused! She told me the 1 at the beginning is for someone who resides there so I don’t know what the heck that happened… I’m a resident of Ontario, we should have a 4 or 5 in front. I called services Canada and they were supposed to send me an email with the information of how to fix it but they haven’t. I’m gonna call back tomorrow.