> is that surprising?
No. It's a difficult problem to mitigate.
There are always going to be some students who want to learn the minimum possible to pass the exam, and who will never work with the material again. Although I do my best to be respectful of such students (indeed, in some circumstances this can be a perfectly rational point of view), my pedagogy is aimed at the student who sees my class as something more than a meaningless hoop.