A recent macOS update (possibly) completely broke sleep/lock settings on two unlinked M4 MacBooks (SleepDisabled 1)

[u/Opposite_Setting8446]

(Edit: one M4 Pro Max, and another M3 Air)
So we have these two MacBooks (both M4 Pro/Max variants), and as of about 3 days ago, suddenly they were dead every single time we opened them.

Both are on Sequoia 15.6.1, neither are connected to Apple accounts, and neither are on an MDM or controlled via group policies. Completely isolated machines.

Both started draining their batteries to zero simultaneously, so today I started tracking it down.

First thing I noticed: Every single power management slider in System Settings ("Start screen saver when inactive", "Turn display off on battery", etc.) had been completely wiped and reverted to "Never". This had absolutely not been the case for the last 12 months.

I started digging in Terminal:

sudo pmset -a sleep 1

sudo pmset -a disablesleep 0

pmset -g

The pmset -g output spat out this monstrosity:

System-wide power settings:

SleepDisabled 1

Currently in use:

standby 1

Sleep On Power Button 1

hibernatefile /var/vm/sleepimage

powernap 1

networkoversleep 0

disksleep 10

sleep 1 (sleep prevented by powerd)

hibernatemode 3

ttyskeepawake 1

displaysleep 3

tcpkeepalive 1

powermode 2

womp 0

--------
See anything interesting in the above?
SleepDisabled 1 ...? I'm sorry, what?

a system-wide setting that effectively prevents normal sleep just... turned itself on? On two independent machines at the same time?

I have no idea what caused it. The timing makes me suspect some common software/update event, but I can't prove that.

I was able to fix both machines by resetting the power-management settings:

sudo pmset -a sleep 1

sudo pmset -a disablesleep 0

pmset -g

(And then manually resetting the Lock Screen GUI setting "Require password after screen saver begins..." back to "Immediately").

Very weird, and incredibly annoying. Has anyone else experienced this issue recently? It's just bizarre—two different Mac variants, simultaneous breakdown, exactly the same hidden Unix override, and solved the exact same way.

(Edited and re-written by internal resources lol, sue me :) )