Hello everyone,
I’ve recently had the most peculiar thing happen. While on an international train, my FP4 had a system notification saying “Switched to SIM1 for mobile data access, you can change this in the settings”.
So into the settings I go and find out that the setting for automatic switching was turned off. That SIM has not been used for Data nor does it have a subscription which allows flatrate data…
I don’t know whether this bug is specific to my situation or if it is more widespread. I hope it’s a niche problem with not many people concerned, but regardless, a little hint about this option having become available in Android 15 would have been nice before the SIM switch actually occured.
Background infos:
I was on an international train from the Netherlands to France and have 2 SIMs installed, a Dutch one (eSIM) and a French one. Once the train passed the French border, my FP4 showed the notification and had indeed switched network as could be seen in the statusbar in the top of the screen.
If any costs come from this I’ll be very disappointed and disturbed by this feature/bug. Especially since the slider appeared to have been off by default.
If anyone else has ecountered the problem and knows more, I’d appreciate knowledge on the matter. If someone reads this prior to going abroad, check this setting in your phone! Go to the Networks setting and check the options behind both SIMs.
Kind Regards and have a great year end period.
and a 
SIM in my phone and regardless of the selected data preference and the toggle above mentioned being set to off, it stubbornly switches data on its own. It seems to do this to avoid roaming connections - which seems to be a mostly useless “feature” in the EU.