One key double clicks, but only single click is registered

[chnapo]

See photo - this key, when tested, registers only one clicks, but always writes two characters - in my language, it should write " ´ " and it writes " ´´ ". No other key does this. I doubt this is a mechanical issue because when doing keyboard test, only single stroke gets detected, so it should be software issue..?

[chnapo]

Solved - it was virus. Windows deffender on W11 would detect some stuff and remove, but it seems that it did not catch all, even with deep scan that took overnight. I ran malwarebytes and after 5 minutes I am virus free. At least it seems so. My keyboard works OK again.