Help 4G signal on with WiFi

[undergone]

Is this common? I had an S3 where the caller ID app was causing the 4G icon to stay on but I can't figure out this phone.

The 4G LTE logo always stays on even with WiFi fully connected. T-Mobile M8.

HTC support lady said hers does the same. Any insight?

 

[Blade of 3]

The symbol will stay up in the notification tray but may not be running. I believe there's a setting that will automatically use the fastest of the two but only one at a time. Usually the WiFi will be the only Internet going through when both are connected.