Inspiron 16 7630 2-in-1 Won't Wake up from Sleep When in Tablet Mode?

Anyone else experience this? When I have my Dell Inspiron 16 7630 2-in-1 in tablet mode, if I walk away for a while and come back to it in sleep mode, it does not respond to any stimuli to bring it back from sleep mode -- that includes tapping the built-in keyboard, tapping my bluetooth keyboard, moving my mouse, touching the screen (with my hand or with the pen.) I have to flip the screen back to laptop mode. The instant I do, I can 'wake' the laptop up. Is it the end of the world? No, but it's certainly an annoyance. Is this an intentional limitation or is there something wrong with my particular laptop?