Please make sure that the bracket has been aligned properly on the 12.9" iPad Pro. If the alignment is wrong, the Calibrator App will not be able to be used correctly to align the color and depth images together.
This becomes especially important if you are using the Wide Vision Lens with your Structure Sensor. If you are using the Wide Vision Lens, please make sure that you calibrate the sensor in the Wide Vision Lens Mode after confirming that the bracket has been attached to the iPad correctly. I've added a screenshot of the two different calibration mode for reference.
You can find more information about that specific bracket here: https://structure.io/getstarted#ipad-pro
Let us know if this helps!