CC 2019 will not Merge all my images to create a panorama

I've been using Photoshop for many years to create panoramas however this version, CC 2019 won't incorporate all my images intended to be included in my pano. For example, I've taken 9 images that take in half of a college basketball arena. Yes, I've lapped the images by approximately 1/3 as I have for 10 years . If I select these 9 images in Bridge then select Tools, Photoshop, Photomerge, a Photomerge menu appears and from that menu I see my 9 images and select, Cylindrical, Geometric Distortion Correction and Content Aware Fill Transparent Areas, then OK, the process will begin.........

However it will only include 5 or 6 of the nine images omitting 1/3 of my panorama. It will produce a pano using six consecutive images  from the group but no more than six. In years past using CS5 the Photomerge process would incorporate 30 or more images, sometimes 3 rows tall. Some of my completed panoramas reach 4-5 GB in size when complete. What is the problem with Photomerge?

This is a new iMac 27 machine running OSX 10.14 Mohave. I currently have 40GB of 2400 MHz DDR4 RAM and the processor is a 4.2 GHz Intel Core i7.