Update: Apple has just released the macOS Monterey 12.2.1 update that claims to have solved the issue.
Following the arrival of the latest macOS Monterey 12.2 update, multiple Mac owners have been reporting a new battery drain issue that seems to occur while their machines are in sleep mode.
According to MacRumors, it appears that the issue is caused by Bluetooth accessories constantly waking the machine, resulting in a "DarkWake from Deep Idle" state, which in turn drains the battery. After looking through the Terminal app, users concluded that their devices kept "waking up every few seconds all night."
The issue was flagged across the MacRumors forum page, as well as multiple social media platforms, including Reddit and Twitter.
"Battery went from full to 0% while on sleep mode overnight," one of the affected users shared via Twitter.
Users have been reporting the problem for the past several days now, however it's hard to determine the scale to which it has spread since there's no confirmation that it affects anyone who's installed the new macOS update. Based on the reports, it's clear that the bug is present in both Intel and M1-powered rigs.
@ Apple tweeps: macOS 12.2 breaks something related with bluetooth + sleep/wake. Looking at `pmset -g log`, it seems like it spent all night waking up every few seconds for bluetooth and drained all the battery. [FB9862509] https://t.co/5IF81PVw3P pic.twitter.com/qczeDKD5oXJanuary 28, 2022
In an attempt to resolve the bug, some Mac owners opted to install third-party "Bluetooth snoozing" apps that are supposed to temporarily prevent Bluetooth devices from waking the computer. One Twitter user wrote: "I installed Bluesnooze as a way to make sure that it sleeps when I close the lid when the battery is not connected."
Other Mac owners shared that disabling Bluetooth and unpairing Bluetooth accessories also does the trick, though obviously, this fix is far from ideal.
Apple Support has responded to a few users via Twitter by sharing a link to its guide on optimizing Mac's battery life and suggesting users to contact the team through DM. One of the responds read: "We heard you may be having some issues with your battery after updating to macOS Monterey 12.2 and we’d love to help. Let’s meet up in DM so we can investigate things together."
Tom's Guide has reached out to Apple and will update this article upon reply.
So it looks like Apple is aware of the issue, which leads us to believe that a fix might be coming in the next macOS Monterey 12.3 update, the beta for which was already released just a few days ago.