@Russ I added a different command (to close the calculator), and I'm seeing the same results as with the sleep command: It doesn't work when triggered from HA, but does work when triggered via the website or directly via the TRIGGERcmd agent.
I'm not using parameters (though I have tried doing a command with parameters, but that also didn't work, and yielded the same outcome of the log recognizing that a command was sent from HA, but not actually performing the command on the Macbook)
Here's the screenshot from the GUI editor as requested: