Every time when I open a text editing application, and I select a word, in the Menu bar->Edit will flash and after some observations, I found that it is Command C (copy) being pressed automatically. And it does that for every application I open. And when Command C is not a part of the shortcut for some program, Mac will beep to signify that Command C is not a valid action.
However, when I open the keyboard viewer, the weird automatic-Command C behaviour does not show up. That makes me wonder if it's a software/system issue that my MacBook Pro has. So I restored all the hotkeys/shortcut input and it still does not work.
This has boggled me for a while now and I never had the chance to take care of it.