Ghost update: You will only notice this when you log in to MyCIC acct (NO email). There would be something like “application updated/(sth I forgot)” showing at your PR case instead of “submitted”, which is the status showing most of time. After opening the case and going back to the main page, the status goes back to “submitted”.
You won’t receive email notifications about MEP, but IP1 and PPR (or any additional infor needed by cic I guess).
The email you received should be for sth updated at the background section in your case. So I believe it’s IP1 but not for MEP, since IP1 usually comes along with MEP at similiar time and MEP itself won’t receive any email.
FYI,
https://www.canadavisa.com/canada-i...application-stages-and-what-they-mean.576171/
And there are plenty of similar answers within this forum or on google. Cheers.