here's a copy of my dont starve together folder...The bug is saved (ie my son starts in the water) the game is "Jesse's World 4/8/18" ...not sure how to isolate just that world so I am sending the entire folder. DoNotStarveTogether.zip
My son and I were playing and I have a map where he died. . he tried to haunt a clockwork rook and somehow he says it pushed his character off the map into the water. Once there he could never get back on land and even after disconnecting / reconnecting he was unable to exit the water tiles. This was in a regular endless game of dont starve together. A possible solution would be to check if the character location is on a valid (non water) tile at login and if the start location is not valid, to move the character to the next nearest valid tile.