Yes all the time

This was actually true for my class. Because the teacher was so behind on things, we would start every year by doing the last chapter(s) from the book of the previous year. This would take a month and would cause the process to repeat itself which forced us to skip some less important chapters altogether. When we finished HS there were around 3 big chapters left in the book which are *fortunately* not included in the final exams before graduation so I guess no harm done?