I have quite a few Sulawesi Snails, and yes they sort of hibernate. I still haven't quite figured out what's going with the 'hibernation' period, but mine will just not move for a whiel. Give the snail a few days and keep an eye on it, just to make sure it has moved from one area of the tank to another. And continue to do the touch test to make sure it still moves. I had one 'hibernate' for a while, after a week and still no movement I touched it's head and it retreated back to it's shell. After more than a week after the touch test and went to do another test, but there was no head to touch, and low and behold it had died. That's the only one I've had die, and I have three left.
You might also want to try throwing a piece of veg (cucumber works well for my snails) into the tank, to make sure the snail is getting enough to eat. Another side note to these snails, they like protein. I've caught my snails eating everything that sits on the bottom of the tank be it flake, pellet, veg, frozen shrimp, a dead cherry shrimp it's all fair game as far as they're concerned.
Hope this helps.