Keyboard register output with fast clockrate is null/zero

[VerdichteteEnergie]

I noticed that if you keep pressing the button on keyboard when the clock is fast, a zero is output by the keyboard register.

Here is a short video where I show how the output is given at low clock versus high clock:

keyboard.MP4

Can anyone help?

P.S. this question is taken from an old thread which I closed (to avoid duplicates)

[VerdichteteEnergie]

I want to try to get the value of the key to be output when the key is pressed permanently. So that the output is not null but the current value in register.

I've tried using a JK flip-flop and a another register to hold the input for a full clock cycle.
Like this:

So that the input is output from the register during the high edge and low edge. The register can only receive a new value with the next high signal.

I think that worked. But it doesn't change the fact that zero is output when the clock is fast (like in the video above).

Maybe someone can help me or give me a hint?