Update after 1 hour:
I booted after a shutting down from Horizon and inserting the dongle after 12 seconds. After inserting I got the green, blue blink. I reinserted the dongle and got no LED activity. One hour later I pressed power and inserted the dongle. It pushed the payload and boot Horizon (SX OS). Battery was 85% at initial shutdown and 85% on booting an hour later. After booting I shut down as soon as battery was at 84%. I'm not going to insert the dongle this time. I'm pretty sure that the percentage will be 80% or less when I boot after an hour. I'm fairly confident that inserting the dongle while in "zombie state" powers the Switch off fully.
Our results will be a little different because I did 2 hours in semi-rcm, but here's what happened:
2 hours ago, turned off switch through horizon, did not insert sx pro dongle.
Insert sx pro dongle to "zombie" switch, blue light blinks one time.
keep dongle in, press power button, blue then green light on dongle sx os boot screen on switch
battery was at 100 is now at 92.
1 hour ago I turned off a virgin switch from horizon. Turning it on now,
battery was at 100 is now at 100.
This might suggest you're right
@DocAmes1980, there's an ez way to really power down with auto-rcm if you have the dongle handy.
Now, why does it go into this weird mode in the first place?
Seems like on a stock console, stock horizon issues a proper shutdown command, as my switch's battery life did not drain.
In SX menu, where you can shut down the console, the proper shutdown command seems to be sent, as users report less drain.
But in cfw, at least with SXOS, the shutdown isn't complete, or something like that, and users will see battery drain as a result.
Somehow, when in this semi-shutdown state, the switch will act like it is in RCM, but doesn't accept payloads. Seemingly attempting to send a payload to the switch while in this state will actually shut it down, all the way, no funny business.
It's as if it's not autoRCM or horizon that's the cause, but rather cfw?
@Kubas_inko Does your trinket light up if you power down from stock horizon, not cfw? With auto rcm, does it light up? Without autorcm, does it light up?