My XA2 is a dual sim version. My 5th Sony / Sony Ericson in a row, and I absolutely love it. Here in SA (ZA) we have a provider called rain and they provide only data and only on LTE/LTE-A CAT3, no WCDMA, no GPRS, no SMS, no calls etc.
So I have a Telkom Sim for calls etc, and a Rain sim for data. Sometimes I travel through areas where there is no Rain signal. Once that happens it will NOT EVER connect to rain, unless I switch off the rain sim in dual sim settings and then switch back on. 5 seconds later I have full signal an up to 300MBit/sec data.
The above cause me to sometimes lose data connectivity and then my messaging does not work. People try to get hold of me and it is an issue. This is a very frustrating issue, as all works, but the connection needs to be triggered manually.