You are correct! That’s why the platform moves sideways, not forward, because the camera would have had trouble climbing over the invisible barrier. This was my first solution, but it may not be the best.
I have seen some other solutions where the platform has the invisible barrier on the side opposite to the camera, then the whole platform turns 180° in a split second before it moves in the other direction, stopping the camera falling backwards. Another solution could be moving the invisible barrier down to allow the camera to pass, then moving it back up when the platform moves.