Not running on an IdeaPad and showkey works here:
kb mode was UNICODE
[ if you are trying this under X, it might not work
since the X server is also reading /dev/console ]
press any key (program terminates 10s after last keypress)...
keycode 28 release
keycode 125 press
keycode 125 release
keycode 125 press
keycode 125 release
28 was the [enter] being released and 125 was meta being pressed and released twice.
So I’ve edited your title to reflect this important new information and let’s hope someone with your hardware can confirm / deny, because my conclusion from the above data is:
Change the keyboard because you have a hardware error.
(While waiting for someone with an IdeaPad: do you have an external keyboard you can test???)