These four trains will be daily as of June 22, which will bring the entire Corridor back to the same schedule on every day of the week:My guess is he's looking at the odd corridor trains that only run 4 days of the week - 2 in each direction Toronto to/from Ottawa and Montreal respectively. At least one had been daily in the earlier timetable but dropped in frequency when a third was added to the route in this latest version. I interpreted the change as a sign leisure travel on and around weekends was returning faster than business use.
"The following 4 trains: 66, 69, 643, 40 will resume daily service (7 days per week) starting on June 22, 2021."
https://www.viarail.ca/en/plan-your-trip/service-status