Is tv setting for "keyboard" turned on? Like tv is expecting keyboard input. My d series has a keyboard function. Also check what Bluetooth devices are synced to tv. A keyboard or phone somewhere in house may have connected. I know after most tv updates, Android or firmware, crazy settings get turned on off that I never used and I have to hunt down the culprit. Go through all settings and look for anything connected that shouldn't be and anything turned on that shouldn't be that would be an input or input device.