I don't select 4G in the network settings. I rarely go to LTE covered areas anyway.Sorry for the typo.
If you are in areas without LTE I suggest turning off the LTE radio if you can.
My sister in law had similar problems with her Galaxy. Since Smart LTE coverage is in selected areas only her phone would keep going back to 3G/H/H+ and LTE depending on the place. This seems to have resulted in heavy battery drain so I turned LTE off. My sister in law who uses the phone says battery life improved. She turns on LTE only when she streams video in an LTE covered area.
When LTE coverage expends, this won't be necessary anymore.
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