Lightroom/Camera Raw: Cannot merge panorama after updating to 10.14.6

This has made it possible to work again, but it seems I can only do 5-7 HDR pano merges before the merge freezes up and I have to restart Lightroom.

FYI, I have found that although a merge is now working (even with very large file sets), it is not possible to merge 2 separate panoramas in a row without restarting Lightroom.

Good morning everyone,

This thread concerning difficulties with merging panoramas began about a month ago. At that time I posted a comment offering a 'solution' which suggested changing the file names of the images going into the merge process. A lot of highly technical discussion followed on most of which was of no particular value to me but it seemed to lead to solutions for at least some people. All good.

My purpose with this post is simply to place into the record another instance of the merge function failing until the file names were changed. By 'failing' I mean: on invoking the menu command, nothing happened. That is, the system behaved as if there had been no interaction whatsoever. I did it again (right-click/Photo Merge/Panorama). Same result: nothing, not even a flicker on the screen.

The images came from an iPhone5 and were imported directly from the phone so the original file names were of the form "IMG_1234.JPG". The renamed files have file names like this: DIG yyyy.mm.dd-seqno.JPG, e.g.: "DIG 2019.09.10-001.JPG" .

I'm running a MAC, macOS Mojave V10.14.6, Lightroom Classic version: 8.4 [ 201908011719-03751b60 ].

When I wrote my first post and this one I deliberately placed the word 'solution' in scare quotes because my suggestion seemed very much like a not-solution, more like a goofy, blue-sky coincidence. How the file name could influence the behaviour of the merge function is, I readily accept, in the realm of the weird.

But empirical evidence at this office suggests there is a connection. I have observed this behaviour now 4 or 5 -- perhaps more -- times. Once again, I'm not looking for some kind of solution, I'm just reporting behaviour that I observe at this installation.

Cheers,
Koro