I'm going to start from the top. Let's say you want to play repeated notes, and that is not even very fast, like the come together solo or something, pretty basic, right? So you strike staccato notes and most of them either don't register at all, or are with weakened volume. For me the problem extends though. If I play the note very staccato and fast like a brass stab or something I very often hear repeated notes - meaning that the keybed goes back to default placement, and bounces back in so much that it activates a "stutter" second note. I can literally see it . So the problem seems to lie in the fact that the action is slow, and also loosened so much that it actually either doesn't bounce back fast enough to activate my second note or in the case of a single fast staccato strike sounds like a delay.. The only way to address that so far is to play with a different technique, but I could never get used to it and it's nearly impossible especially playing percussion type of stuff like Clavinets, stabs, staccatos and so on.
Maybe it's time to go to a professional keybed techician and maybe he can do something, but since it's my main board I don't have the option to take it to the doctor.
Yes, I've played on the waterfall and also the HA action from nord and don't have this problem there. Take care!