crash with box clip

We have a crash when clipping using box filter in parallel. Here is how to replicate:

• Linux, 5.8.0-RC1, remote server (32 ranks).
• Open Watney's .exe dataset. All vars on. Apply.
• Clip. Box clip. Apply.
• Turn off Invert, turn on Crinkle Clip. Apply. Crashes.

This shows up when not clipping all of the dataset, but it is somewhat harder to replicate.