Looking at the Air Canada Flight Schedule, here:
https://services.aircanada.com/porta...ABC975DFD72085
AC only flies to AMS on Wed, Fri, and Sun, and we would expect a return back to YYZ on Thurs, Sat, and Mon, The pdf flight schedule does not show the Monday flight, however the booking engine and google flights are showing the flights correctly.
As for the OP's expectation of a Friday return, there would be none since there is no Thursday flight to AMS.