Yes, the P1 email is sent when the final decision (approval) has been made. However, you're not a PR yet until you receive your eCOPR. Quitting your job may still have an impact on the application if it was relevant for your PR stream. You should check the section "Changes to your situation" in the P1 PDF you received if it mentions changes to your job. It's entirely possible to get approved, but not become a PR. For example, if you decide you're no longer interested (as mentioned in the P1 PDF). The P1 PDF also states: "If
you answer yes to any of the above, please provide details as further assessment may be required depending on your situation."
Note that this is just my opinion and not legal advice. I'm not an immigration consultant.
Thanks for sharing your opinion. It doesn't mention anything about the job in the section "Changes to your situation" in P1 PDF.
So, I think I should be fine .
Below are the only changes which were mentioned in the PDF:
You get married, divorced, enter a common-law union, or become separated from your spouse.
In the event of the death of
o the sponsor;
o the principal applicant; or
o any accompanying family member.
You, or any of your family members, give birth to or adopt a child.
You, or any of your family members, are charged or convicted of a criminal offence.
You, or any of your family members, are no longer interested in becoming permanent residents of Canada.