Battery drain when switching from wireless to 4G.

[ligius]

I've noticed a battery issue that hasn't been fixed in any of the last updates. Whenever I go from zero cell reception and full wifi signal to an area that has cell reception and no wifi signal, some applications will not connect anymore (e.g. Maps, Signal, Whatsapp, etc). This is 'fixed' by toggling the airplane mode on and off..
The same thing happens in reverse, when going from a cell covered area to one which only has WiFi. Same fix again.
If the fix is not applied, the phone will be seemingly offline for hours, though some applications will connect. The signal icons will show a 'connected' status. The phone drains battery much faster (3-4%/h instead of 1%), though nothing will show up in the usage.
Some technical information, in case it's useful:
cell mode set to 4G/3G
WiFi network is Wifi6
WiFi calling is activated
Mobile data is activated
Bluetooth/NFC are off

[dron39]

Irene2_ASUS

Hi @ligius @lucckk @nishusumi,

Have you notice an improvement after the latest release 51.103?

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I noticed that device running on .103FW is not warm anymore when it's not used. But regarding battery time and screen on time, I think there are no changes since .83FW update.

[ligius]

Irene2_ASUS

Hi @ligius @lucckk @nishusumi,

Have you notice an improvement after the latest release 51.103?

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Sorry, no improvement in this area noted. I still have to manually toggle airplane mode to get connectivity back, every time I disconnect from a WiFi network.
Using SIM slot 1, haven't tried the second slot to see if there are any changes.

[ligius]

Just as an update, seems that I haven't gotten any issues since I've turned off the option to 'keep mobile data always on' in developer options. Not a definitive answer, but maybe more people can report if disabling the option helps.

[ligius]

Sorry to spam, but that wasn't the fix. However, I now only need to toggle mobile data off/on, after disconnecting from WiFi, instead of toggling airplane mode. I'm on the latest build.
Charging is capped to 90%, if that makes a difference.
Not all applications lose connectivity, but an easy way to test is: go to the left-most screen and refresh the news. If it does work, click on one, open it in the browser - the browser will refuse to load the page. Toggle data and not the page loads.