LTE problems are also present on other ROMs, even on 7.x Global Stable. I'm on T-Mobile 4d network and very often when changing from 4g to 3g on certain location, the phone become unreachable on the network. There many reports on this issue on many other networks and countries. It is even more interesting that in some cases you can dial from the Mi5 but no one can dial to you. I have this video recorded and I can post it here.
When selected "Prefer 3g" no issues with network at all.
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