Few things you have to check
Your application will not even rotate if the screen is in locked or in off state so nothing will be called.(It happens because how application/activity can rotate if it in background, same like home key press)
Make sure you are not calling finish anywhere in the app when it goes in background.
Also check, is your app getting crash when you keep it in background ?
Press home button while app is running and bring it in to front using recent apps screen.
Check if onCreate()
is calling again. If it is than your app is crashing or finishing when it goes to background.
I have tested in variety of devices almost 10 different, including Sony Xperia Z, Samsung Galaxy s3 , Nexus 4(as mentioned in comments)) and it is working fine.