Network mode changes on it's own
So I have LTE where I live and under Menu > Settings > More Settings > Mobile Networks > Network mode = LTE/4G/3G/2G.
Lately, I've noticed that when I leave LTE coverage and then come back, it will never go back to LTE. I go back under Menu > Settings > More Settings > Mobile Networks > Network mode and notice that it is now set to 4G/3G/2G. I have to manually switch it back to LTE/4G for it to pick up LTE again.
I even tried dialing *#2263 and setting it to automatic there but it still does the same thing. I have also that when on LTE and using data, it'll just stop working and go back to 4G again.
Anyone else seeing this issue? This hasn't been a problem until I cam back from my overseas trip (which I had the phone in airplane mode the whole time). Not sure if that has anything to do with this issue but just thought I'd mention.
Any help would be greatly appreciated!