WorldEdit version: Forge-Official(7.2.0-SNAPSHOT+5332-0cb1eea)
Platform version: Forge 33.0.37 1.16.2

Describe the bug
When I ran the command '//gmask "##walls || ##fences"', the console threw an out of bounds exception rather than a standard error.

To Reproduce

1. run //gmask "##walls || ##fences"

Expected behavior
An error explaining that you can't do that.

Screenshots

Additional context
Here is the debug.log for more details.
debug.log