Can't clear comments on VMs

On the exe.dev web console the help message is:

Comments are short, plain-text notes shown next to your VM. Max 200 characters; HTML metacharacters not allowed. Submit empty to clear.

If I submit an empty comment I get:

usage: comment <hostname> <text>

If I submit and empty string "" I get:

comment must not contain HTML metacharacters (< > & " ' `)

I get the same in the ssh console:

exe.dev ▶ help comment

Command: comment

Set or clear a short comment on a VM

Usage: comment <hostname> <text>

Options:
  --json output in JSON format

Examples:
  comment my-vm staging copy
  comment my-vm "" # clear the comment
exe.dev ▶ comment ficks-bravo.exe.xyz ""
usage: comment <hostname> <text>