I have this too. I think the autorotate notification is actually a a side effect of what's actually happening, and that is the SB is switching between tablet mode and laptop mode. When it goes from laptop mode to tablet mode, you also get a notification about the autorotate being enabled. This happens randomly for me, and has become annoying enough that I've turned off the setting that automatically goes into tablet mode when I unclip the tablet. Seems to happen a fair bit when plugging or unplugging it from power? I am fairly confident this is a software issue that will be fixed in time.