There is a Notice on the CRA's website, regarding the availability of tax slips in My Account, Represent a Client, or through the Auto-fill my return service. 

Availability of tax information
Some 2024 tax slips are not yet available in My Account, Represent a Client, or through the Auto-fill my return service. We recommend using the slip provided by the issuer (e.g., your financial institution or employer) until the slips are available.