Lol haven't heard of that or had that issue. Are yo sure your wifi isn't turned on? If there are networks nearby and wifi is on, it will connect to one. If it finds one and can't connect a question mark will display next to the wifi icon in the status bar.
Conversely, Ive had issues when I have wifi connected and the 4g icon displays on the status bar simultaneously. The 4g icon goes away after a few seconds. Not sure it actually connects to 4g, which will piss me off.
I am having the same issue. Also I know that I have cut off the WiFi. I will be using the mobile hotspot app and then it will stop working. I look in my settings to see that WiFi has cut it self on and disabled my hotspot. It happens more when I use the hotspot app.