I've noticed that traps take me out of Ethereal Jaunt when I step on them. Of the two, one even damaged me with frost damage. This seems like a bug. I shouldn't even set them off while ethereal, let along take damage or be taken from etherealness by them. In both instances, it said attempting to interact with the physical world causes me to break etherealness... I assume because I rolled a reflex save; however there's no reason to dodge at all if you shouldn't even be setting it off and cannot be hurt by it.