I can´t remember this happening in the old Dragon
Still they have updated some stuff like Class Acts, I imagine because those are likely to be added to the D&D Compendium soon.
Still Phanton Chasm still has the issue with duration.
Hit: 2d6 + Intelligence modifier psychic damage, and the target is prone and immobilized until the end of its next turn.
Miss: The target is immobilized until the end of your next turn.
The target is immobilized for a longer duration on a miss.