I have been trying to use the new Panorama feature in Lightroom CC. Tried stitching 6 RAW D810 images together, but it reads/considers only four from either right or left. First I thought it might some issue with my image overlap, but the Photoshop created the pano without any issue. Currently I am on trial version. Does that limit anything or there is any limitation to the LRCC itself.
Have you tried stitching the first four and the last four of the six to check for image overlap being the problem? Maybe PS and LR aren’t using exactly the same code and one works and one doesn’t if the overlap is a bit hard to detect.
It’s also possible you’re running out of memory since the source images are rather large.
LR’s maximum image dimension is 64,000 or maybe 64K=65535, but I don’t think six 35MP images would be running into this. To make sure check to see what the panorama width in PS is in pixels. I guess it's also possible that LR's maximum panorama is limited to half the normal limit or 32,000 pixels, which your panorama could be larger than.
You could try uploading the images to dropbox.com and post a public share link, here, for others to try that might have computers with more memory.