This phenomenon occurs because the "Dynamic Backlight Control" function is adjusting the brightness of the screen when menu items (on-screen displays) or subtitles are detected.
To minimise this effect, configure the Adv. contrast enhancer setting by following the steps below:
- Press the Home button on the remote.
- Select Settings.
- Select Display in the TV category.
- Select Picture.
- Select Advanced settings.
- Select Brightness.
- Set Adv. contrast enhancer to Low or Off.