Uhhhhh, so, I found a glitch. pic.twitter.com/DsPf5G6RjK— Swiffy22 スウィフィー (@Swiffy22) March 19, 2017
Looks like players are stumbling upon a glitch that lets link walk underwater. It seems the glitch has something to do with existing the water while climbing a wall. The game gets confused and thinks Link has climbed onto land when he's actually dropped under the water's surface. Check out this thread for info on trying the glitch yourself.