first 2~3 months i've had it, its always shown as LTE+ on tmobiles network. no issues at all. then past month, its been dipping into LTE, then hspa and sometimes not even getting signals. I've had tmobile replace my sim. its gotten marginally better if at all. dont know why suddenly things change. ive been with tmobile for a long time and in excellent standing, so i dont know the reason for this discrepancy. nothing about my usage pattern has changed.
i have a crazy theory -not knowing the mechanics of things like this -that something about the way this phone interacts with the sim card is a little off causing it to not to be fully receptive. i, of course, base this only on the fact that I've never had to replace a sim card before except to move micro-sim to mini-sim then to nano- sim. i have no scientific sources to back this up.