As it says on the tin really.
I have NHHiker’s version of the script installed and when I shutdown from OMV the Pi’s red LED stays on and a single press of the power button won’t boot the Pi, I been to do a long press to turn it off properly, then a short press to start it.
I also have an Argon one and have noticed a similar issue.
It’s not really a biggie, except now I’m trying the RTC and scheduled shutdown/startups. As the pi seems to standby, but not shut down, the timed startup won;t work.
I’ve tested the RTC and startup by setting a startup time, shutting down then doing a long press to properly shutdown When I do this, the Pi boots at the expected time, so I’m pretty sure it’s a shutdown/standby issue, not a RTC or power up script issue.