Is there anyone having problems after switching from WiFi to GSM data? For me sometimes, not always, it shows 4G data connections and those two arrows next to the 4G logo, but the data connection is not working. I have to restart the phone in order for the data to work. Also another workaround is to go to data connection type at carrier settings and change it to something else that already has GSM/HSDPA/LTE in the name. It started happening a couple of weeks ago.