Client Application Status (CAS) may not show some activities on your file for many weeks. That is because the visa offices and the case processing centres get a lot of information.
In many cases, an in-process file is actually waiting in a queue for initial review. Applications are handled in the order they are received and on a case-by-case basis. The waiting time in this queue can be long. Applications are processed according to the application processing times at a given location.
In addition, CAS does not show some other actions—such as security checks—at all. So it may appear as though nothing is happening to your file, even though you have had interactions with us recently.