Hi @wilkersond1,
There is nothing in Canvas itself that should auto-publish a course.
With that being said, there are many schools/institutions (mine is one of them) that have created auto-publishing scripts that run on a schedule and publish courses based on set policies and schedules. For my institution, we auto-publish any course with enrollments on a daily basis stating on the first day of the term. It may be worth reaching out to your school/institution Canvas team (usually in the eLearning / IT / Digital Education areas) to see if they have something like that in place.
The only other thing I could think of is that your unpublish action isn't being successfully done, but you should see a message at the top of the screen in Canvas when you hit unpublish if that was the case.
Hope this helps a bit!
-Chris