Students are learning a methodology, while at the same time acquiring basic technical skills and know-how. They are building capability in the academic, social and technological arenas. Professionals are presumed to have advanced capabilities. One of the most difficult tasks for the teacher is determining what is an appropriate problem. That may not even be the correct question.
Students can tackle many problems that professional designers work with.
The difference lies in the expectations for the solution. A design brief is used to focus the efforts of the design team. It states the problem, limits that are on the solution, and what the solution must do. Help them understand that they are building capability with technological problem solving, and that they are being graded on this more than the actual product. It is very easy to let the process get out of hand.