When you edit a class and choose to update it and all future occurrences in a recurring series, it can affect any classes that have already been canceled or deleted. Specifically, if you've canceled or deleted a class in the future and then edit a previous class in the series, selecting "update this and all future classes" will cause the canceled or deleted class to reappear on the schedule.
For example, if you cancel a New Year’s Eve class in November but then later edit the recurring series in December and select "Update all future classes," the canceled NYE class will reappear with the new settings.