Lightroom Classic: Auto-stack suddenly inconsistent with Canon 7D

I've used Auto-Stack by Capture Time for years with my Canon 7D for HDR bracketed photos. Recently, I auto-stacked a folder of images, and got wildly different results from stack to stack.

I shoot three exposures: 0EV, -2EV, +2EV and that is the order they are taken by the camera.

When I have them in the grid view, before stacking, ordered by capture time, they are in the correct order. After stacking, the stacks are individually out of order, but in an inconsistent way from one stack to the next.

In some stacks, -2EV is at the top, followed by +2EV and then 0EV (completely reversed).
In other stacks, +2EV is at the top, followed by 0EV and then -2EV (rotated by one place).
In some other stacks, the order is correct.

I've unstacked and restacked several times, and the results are inconsistent. Any ideas what I might try to remedy this? I've spent more time re-ordering my auto-stacks than I would have spent stacking the images myself.

Lightroom Classic CC, 8.2 Release
Windows 10 64 bit, 1809, 17763.379
32Gb RAM, i7-6700 3.4Ghz CPU
Canon EOS 7D, shooting raw CR2
Imported to LR Mobile on iPad, and synced to LR Classic CC Desktop

Thanks,
Mike