I think I must apologize for acting too hastily. After deeper reading and experimentation, I surmise that the output of the cameras is not used to measure disparity; instead, the rectified left and right images are used. In the latest version of DepthAI it is possible to show the rectified images. There appears to be no difference in the height of horizontal objects in the rectified images. Good!
However, now I think I see another seeming anomaly. In my experiments, I also display the color camera preview and center the color camera on a vertical edge. The mono cameras see the edge at different locations, as expected; it is to the right of the middle in the left image and to the left in the right image. However, in the left rectified mono image the edge is in the middle of the image. And in the right rectified mono image, the edge if farther to the left. And finally the edge that should be in the middle of the depth output is instead located at its location in the right rectified image.
I know that disparity is calculated in the right image. I'm not using depth align. I was hoping the default was CENTER, but that seems not to be the case. So the default must be RIGHT. Does this make sense?