Originally Posted by
freecia
Did you turn off LTE via Settings->Cellular? Global Roaming is mostly 3G. AT&T does have some international LTE roaming agreements and T-Mobile seems to get a bit in Germany, but in general, LTE roaming isn't enabled. It could be that the phone kept on trying to authorize on the LTE network, even if the speed shown was 3G. Many carriers still operate them as slightly different networks and it could be that the roaming agreement wasn't applied to the LTE profiles.
Thanks for the advice--I'll have to try that the next time I go abroad. I was originally afraid that if I switched off LTE roaming, all data roaming would be switched off.