they do
https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/corporations/corporation-payments/understanding-interest.html
Refund interest
We pay refund interest according to the prescribed interest rate. Refund interest is compounded daily on an overpayment up to and including the day the overpayment is refunded, repaid, or applied.
When we refund or apply an overpayment, we pay refund interest from the later of the following dates:
the date of the overpayment
the 120th day after the end of the tax year if the return for the year is filed on time
the 30th day after the date the return was filed if it is filed late
In the case of a repayment of tax in controversy, special provisions apply.