System in Off mode, a smoke detector activated, then the system switched to Away. -- normal ?

When we had a smoke detector activate while the ss3 system was in OFF mode during the day,
the system apparently switched to AWAY mode,  and then a bunch of  sensors activated--motion and entry,
while we were moving around the rooms and area to  check for smoke.  

Turned the system OFF, and they stopped.      

This  did not happen with the  old  ss2 system that we upgraded  a few months ago.  System stayed in OFF mode,
and the only alarm was for the smoke detector.    

Is that normal, or is something not working right or  configured wrong ?  

Thanks.