@brian_hiatt-ale
Did you also check the box that students can only participate between these dates?
See this lesson from the Canvas Instructor Guide: How do I change the start and end dates for a course?
In particular, one note at the top says:
Course Override Dates
Course override dates are only created if the Student Participation checkbox is selected as part of creating start and end dates (both dates are required). If the Student Participation checkbox is not selected in Course Settings, students can participate in the course before and after the start and end date, and participation dates will always be determined by the term dates.
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