Not how the levelscaling works    For example if a player clears out a dungeon at level  the enemies would be skeletons If the player returns at level  or above it could be full of trolls The enemies weapons are also leveled along with the treasure the player can find in chests and on enemies bodies  For one thing its very rare and near impossible to find trolls at level fourSecondly trolls would never ever replace skeletons because they are on completely different leveled listsThe only thing that would replace a skeleton is another skeleton or eventually a lich