Why TRV Extension needs Medical?

[SHENJUTI]

Hello Members,
My mom came in last December on TRV. She didn't do any medical while apply for TRV. We applied for visitor visa extension in May as she couldn't go back for COVID. Today I got email from IRCC requesting for her medical test.
I am wondering why they need medical result now? Is this a part of process?

 

[k.h.p.]

Because anyone who stays longer than 6 months is required to do a medical exam.

 

[SHENJUTI]

Thanks