I’ve stumbled into various quirks across many systems over the decades, and, iirc, it was actually something like sudo shutdown -t secs now [(?! wat)] that resulted in reliable shutdown, contrary to all logic and presumed would-be redundancy. But, yeah, you’d think so. I don’t know what the current state of shutdown’s like. That was from like over 15 years ago, back when I had a X60T thinkpad I’d actually shutdown.