I didn't have any problems about the full sequence of lesson when extracting out. It may be related to the application you are using for extracting.Anyone else didn't get the full sequence of lessons when extracting? Is that expected?
My lessons are like 1, 3, 6, ... , 12, 15, 16, ..., 20, 24 (that is, missing 2, 4, 5, 13, 14, 17, 18, etc.)