This problem seems just as bad or worse for Griffith's EM. :(
I have also had problems where my own students give me solutions that
look just like the ones I gave out to the class last year or the year
before - yes I switch problems but for some courses like Quantum you
dont have alot that they can actually do to choose from.
This online "cheating" just makes access easier - it was always an
option for students in the past - I think awareness is key.