Occasionally or for me nearly every time I play through Desert Temple, if the bonus room spawns where you enter from the right of the screen, the Secret Door cannot be entered after it's been opened. Due to the POV of that level generation, you do not have line of sight on the secret door. Once you flip over to the platform, the sound of the door opening and the secret play, but you will not be able to enter the room since you can't click on the door if you cannot see it.