I have the LCD timeout set to 30 seconds with a lock pin.  I left the A+ with the "Connected sensors" main screen showing, and it had not timed out after several minutes.  I switched it back to the home screen, and then it timed out as it should.
Shouldn't it have timed out no matter which screen I was on (and then presumably started over at the home screen after unlock, though I suppose you could argue for starting back up on whichever screen was on when it timed out).
Sounds like a bug.  Minor, but thought you'd want to know.