In both incidents there was an OTA update available for the Nexus 4. This time I received the update notification at some point during my stay abroad. I had wifi connection most of the time, so I assume the update was downloaded using the wifi connection (the roaming traffic is too small for the update by far). I did not install the update until I returned back home. Last time my phone wasn't able to download the OTA update, since I had a custom rom installed at that time. It is possible that it tried downloading the OTA update for the entire stay back then (and even before and after - I noticed increased traffic over normal mobile internet at home). I switched back to the stock rom a while ago and thus was now able again to receive official OTA updates.
This time I was staying for 8 days in Chile, last time was around one week of Italy. My provider is Orange Switzerland.
What can be the cause of this? I am absolutely certain that data roaming was disabled in Android both times. Could it be that Android somehow bypasses the disabled roaming when checking for OTA updates? But it would have to do it when already knowing there is an update, so what's the point of doing this? Or could it be a provider initiated connection to notify the phone of the update? What can I do to prevent this from happening in future?
Thanks for any input!