It sounds like the lift gate (rear door) angle sensor is out or not adjuster correctly. What happens is this sensor tells the rear door control module the door is ready to be latched which is not happening. Here is the wiring diagrams for the power door locks and rear door operation so we can see how the system works.
Check out the diagrams (below). Please let us know what you find.
Images (Click to enlarge)
Thursday, February 18th, 2021 AT 1:34 PM