Yes, it definitely looks like that.
What I have done so far:
- Cleared the cache of all system apps
- Set 4G as the preferred network type
- Deactivated the secondary (physical) SIM card
- Deactivated ‘Mobile data always active’ in the developer options.
- Deactivated ‘Select network automatically’
- Disabled ‘Mobile data’ for Vivaldi
- And today I installed version 3.5-a15 of e/OS
In addition to disabling ‘Mobile data always on’, it seems to be most helpful to use a Wi-Fi connection. When I get the chance, I will disable ‘Mobile data’ for all apps and try to find out if it is caused by an app.
If anyone else has any tips, please feel free to share them.