I will summarize the things happened from yesterday onwards :
April 26,2021, I received the Medical Request in my CIC account. Didn't get MR of my dependents.
April 27, 2021 , logged into the CIC account, verified the messages again. No MR for dependents at this time.
Called IRCC, after 1 hr wait connected to an agent. Asked about MR of Dependents, she said they may have valid Medical, that is why you didn't get their MR.
I informed her that me and my spouse did Medical back in 2019 and child's Medical did on April 10,2021 as part of his Visiting Visa application.
She put my call on hold for further verification and after 5 mins replied that my CIC account updated 30 min ago with Medical Passed ( I logged in to CIC portal after the call and it shows Medical passed on April 27,2021)
She explained that IRCC extend the Medical of my spouse and mine till April 26,2022 and my son's medical is valid till April 10,2022.
She said no need to do Medical again.
This is what happened today. I am not sure how come the Medical got extended to April 26,2022 and why they send MR?