What I have read from other thread , your temporary visa will become invalid after p1 , so until you get the PR card you cannot re-enter Canada if you are inland , And the second option is you need Copr along with onetime travel visa to re-enter.
I have also got the P1 email today .
@Hyper1013 @the.tq.guy
My spouse also received the P1 email , But Can we send reply only from my email that is (principal applicant) . Please let me know if this happened in your case as well ?