This usually happens because your application is launching a child process or even a parallel process not under the current process. You'd need to use something like Process Explorer to see what the process that is getting launched is. Is that process still under Pega Robotics, or is it now outside? That is the main question you'll need to answer for your self to understand how to hook the application.

First i tried calc.exe which lauch calculator.exe and after that start interrogration stopped. I tried the same for chrome.exe and also the same and for chrome.exe no child process. So this is something else. Please assist. 

I would suggest that you open a support ticket. Someone will need to look at your machine. If you do, please report the ticket number here so the resolution can be added to the post.