Goto settings->more...->mobile networks
Change it from Global to LTE/CDMA (if in Sprint variant) and reboot
I had the same issue as it will disconnect to search for a global GSM network to connect to every few mins and then reconnect to back to its home network when in global mode.
Sent from my LG-LS995 using xda app-developers app
-This is my EVO. There are many others like it, but this one is mine. My EVO is my best friend. It is my life. I must master it as I must master my life. Without me, my EVO is useless. Without my EVO, I am useless...