Diagnosis
The Home Dashboard (the overlay with your inputs and apps) is being triggered automatically. This is usually caused by one of the "Quick Access" buttons on the remote being pressed accidentally or a sticky button.
How to Fix It
Check the remote first. Look at the colored buttons (red, green, yellow, blue) right below the number pad. One of them is likely programmed to launch the Home Dashboard. Press the Settings button on the remote, go to All Settings > General > System > Additional Settings > Quick Start. Make sure this setting is turned OFF. This is the main culprit for phantom dashboard pop-ups. Also, go back to the Home Screen and press and hold the "Home" button on the remote (the house icon). This will let you edit the dashboard—remove any widgets or inputs you don't use to simplify it.
If That Didn't Work
The TV's internal clock or an app might be causing it. Go to All Settings > General > System > Time & Date and set them manually instead of using "Auto." Then, perform a soft reset: unplug the TV from power, hold down the physical power button on the TV itself (if it has one) for 30 seconds, then plug it back in.
Heads Up
If you have any universal remotes or gaming consoles controlling the TV via HDMI-CEC (Simplink), they might be sending the "Home" command. Try turning off Simplink in the Connection settings as a test.