S23ultra: Battery drain in deep sleep took a serious dive after the September security patch

[Ipse]

First time I'm stumped and looking for help everywhere...

After I updated the S23ultra (918W Canadian variant) to the AWHF security patch, the phone is using an insane amount of battery while in deep sleep.
It used to burn 2-3% in 8 hrs, now it's 20 -25%...and yes, in deep sleep, no app reported running by Device Care or Accubattery.

I always do a cache wipe after these updates - didn't help.

In full desperation mode, I factory defaulted the phone - that didn't help either.

Running the phone in safe mode or airplane mode does not fix the drain.

WHAT DID fix the drain is forcing the phone in 4G mode - obviously not a long term solution.

I will add that this is happening at my house where the LTE signal as always been 5 bar (better than -95dBm on band 12) and I have not changed carriers or anything. 
The phone uses normal amount of power when in use, or at least I can't detect deep sleep drain as it's not sleeping.

Looking for suggestions on how to determine if the modem code got busted, if the carrier made their own changes (is that even possible?) etc.

PS I did submit logs through Member  Care, but that didn't seem to go anywhere.

I posted it on the US forum too in case someone else saw the same thing.

[RobertZ]

Under settings->battery and device care->battery, what does it show as using up the battery?

[Ipse]

Nothing, absolutely nothing. Therefore I suspect the modem, given that the issue subsides when I drop to 4G.

I mentioned that safe mode and airplane mode didn't solve anything....

BTW  hope is it OK to post screenshots (I'm new here)? I have tons.

LTE offLTE on

[Lascelles]

I also experience this issue recently after update. I've done the same steps as posted, no results yet. I've also uninstalled some useless "core" apps that haven't been added back to updates yet...

[Ipse]

Yea, doubt it's an app...as I said, it does the same thing in safe mode and also nothing is reported as using the battery...plus the nail in the coffin : if it's an app it would not stop draining when I  switch to 4G.

Samsungs' silence is deafening.

[Helenna]

Hi, I request you to perform the steps in the given link then check the performence of the Battery.

https://www.samsung.com/ca/support/mobile-devices/what-to-do-if-the-battery-of-my-new-phone-seems-to...

Please let us know if the issue persist again after performing the steps.

[Ipse]

Hello,
I already performed those steps and the  battery life has not improved.
Key here is that in 4G mode I don't see the problem, so optimizing apps will not help at all.
I will reiterate that in the same house before the September security patch I didn't experience any problems, I have the phone for 7 months now.
LTE signal is strong ( better than -95dBm on band 12) so that's also not the issue. It has not changed from what it was before the update. 
I also contacted the carrier which reset all the account settings on their end, this didn't help either.

Whats next?

[Helenna]

Hi, we request you to please visit the nearest service center and get the device examine by the technician to know the root cause of the issue.

https://www.samsung.com/ca/support/service-center/

Please visit the link given above to know the nearest Samsung authorized service center.

[Ipse]

Unfortunately there is no center in a 200 km radius.
What should I do in this case - I can't send it blindly to a shop elsewhere.
Thanks

[Helenna]

Hi, In this case we have only option left is Door to Door. I request you to please contact us on Live chat, we will help you with the Door to Door option.

Please follow the below link.

https://www.samsung.com/ca/support/contact/