So lets say the board looks like this:
[D][D][D][ ]
[D][X][D][ ]
[D][D][D][H]
D = Difficult terrain
X = Enemy
H = Hero
The argument was "Would stepping into the difficult terrain squares provoke an attack of opportunity?" I was the one running the game. I would say no because you are not stepping out of a threatened square. The argument that a player had was that you have to use 2 movement to step into that difficult terrain square and he would get an attack because of that 2nd movement cost. Does anyone know of a clear ruling on this?