Not sure if anyone else has had this issue. I'm hoping yes and that there's an easy fix. I find that often, though not always, data connection drops while I'm traveling, possibly when switching towers? My phone will read 4-5 bars, LTE service but phone has completely lost all data connection. It's easy enough to fix by switching airplane mode on and back off again. Data comes right back, but it will remain shut off until I do this. It is incredibly annoying. Turning airplane mode on resets my tether/hotspot connection so that has to be redone as well which is extremely frustrating if trying to do something as simple as work from a train.
I rarely am on the phone (i.e. on a call) when this issue occurs but the few times I have been I will also lose the call. Or if I have switched towers and have yet to enable/disable airplane mode, when trying to call my phone acts up and will freeze once I try to place a call. I have to wait for it to unfreeze, toggle airplane mode on and back off and then I can call again like normal.