You are correct. You will see the lessons change between the new format and old format. The way courses are developed today is that each module is created and then the modules are combined to create a course. This way the exercises are interdependent and we are able to modularize our approach. 

However with this approach as you have seen there may be some times that the content will change presentation views. As we continue to migrate to the new presentation view this should be occurring less and less often.

You have a keen eye and thanks for the inquiry,

Sean
Pega Academy Self-Study Support Team