Sort of a drag.
I was able to finally dialog with support and it turns out that for the early Macbook Pros with retina display, the maximum supported monitor resolution is less than the Ipad Pro’s resolution.
“Depending on the iPad model, I wonder if it might not be able to support the iPad in Retina mode. Based on Apple’s technical specifications sheet for your MacBook Pro, it seems like your Macbook Pro can display at maximum a resolution of 2560 by 1600 pixels. The newer iPad Pros for example have a resolution of 2732 by 2048 which would cause the MacBook Pro to be unable to run retina.”