When an unload commands makes VoiceAttack wait before shutdown(either through pause or loop), clicking the "Stop Commands" button(or the equivalent keyboard shortcut) will stop the command and close VoiceAttack.
However, if VoiceAttack is told to close again(either by the "X" button or Alt-F4), "Stop Commands" must be triggered a second time before VoiceAttack will actually close.
This state can also be induced multiple times, I.E. if VoiceAttack is told to close twice, then "Stop Commands" is triggered, keeping VoiceAttack running, telling VoiceAttack to close again will once again make it require "Stop Commands" to be triggered twice before it will close.
The second instance of the command does not produce any output(write to log, play sound, tts) *until* "Stop Commands" is issued, at which point it appears to run like a normal command would.
Testing with a unique-ish identifier(the second at which the command was started) shows that the second command actually replaces the first command(and each subsequent one its predecessor as well, as long as the sequence of close, then stop, is maintained).
I have the "Cancel Blocked Commands" option checked, though there is no "Command canceled: Another command is not allowing others to execute (canceled: command name)." visible in the log when this situation occurs.
Turning this option off does not appear to make a difference.
Having the "Allow other commands to execute while this one is running" option checked does not appear to make a difference either.
EDIT: In v18.104.22.168, if VoiceAttack is told to close while an unload command is already running, it will close after that unload command stops(either by finishing or otherwise).
The command will not be triggered a second time.