Bug with Course Category Slug

When changing the Course Category Slug in the CoursePress Settings it does not appear to accept hyphens. Here are the steps I took:
1. Set Course Category Slug to "product-line"
2. Save

Pretty straight forward but I wanted to be clear. However, after I made the change all of my course category pages broke on the front end. When I would go to the URL "www.example.com/product-line/my-course-category" I get a 404. If I change the URL to "www.example.com/product_line/my-course-category" then I get the expected result and it shows the courses assigned to the category.

And to add insult to injury if I change the course category slug to "product_line" then the opposite occurs.
1. Set Course Category Slug to "product_line"
2. Save

When I would go to the URL "www.example.com/product_line/my-course-category" I get a 404. If I change the URL to "www.example.com/product-line/my-course-category" then I get the expected result and it shows the courses assigned to the category.

Am I doing something wrong or is this in fact a bug?