need to urlencode the course_id when constructing the registration redirect query string

lms/djangoapps/courseware/views.py

@@ -849,7 +849,7 @@ def course_about(request, course_id):
                     shoppingcart.models.CourseRegCodeItem.contained_in_order(cart, course_key)
 
             reg_then_add_to_cart_link = "{reg_url}?course_id={course_id}&enrollment_action=add_to_cart".format(
-                reg_url=reverse('register_user'), course_id=course.id.to_deprecated_string())
+                reg_url=reverse('register_user'), course_id=urllib.quote(str(course_id)))
 
         course_price = get_cosmetic_display_price(course, registration_price)
         can_add_course_to_cart = _is_shopping_cart_enabled and registration_price