Problems with brightness media buttons

While setting up hotkeys in my window manager I find out that if I would press the brightnessup\brightnessdown button(which changes brightness as it should) and after that go to terminal, pressing 'Enter' there would lead to the change of screen brightness, or in other words the same result as if I pressed the same brightness button again. After checking my window manager config, in order to be sure that there is not problem, I started acpi_listen in order to check if there are multiple button press. It have shown that each brightness button press adds video/brightnessup BRTUP 00000086 00000000 K and each enter press in terminal adds video/brightnessup BRTUP 00000086 00000000 (The same behavior is for brightnesdown but with change of numerical code) So questions are: - What means K in the acpi_listen output?(I have searched it but man-page for acpi_listen does not explain the structure of the output) - What could lead to creation of this acpi events: video/brightnessup BRTUP 00000086 00000000 without K? - If there is no way to get rid of such events, is there a way to ignore events for the button without K? Thanks, in advance