Weird thing is I can still use punch buttons, luckily it rarely occurs and I’ve only had this problem in training room. Is the pcb the problem?
Need to know more about what you’re using and how you’re playing
Sometimes if a button is really sensitive, it’s possible you’re not letting the button decompress all the way, giving the illusion that it’s not working.
Have you been playing for a while? do you notice it doesn’t work shortly after you’ve hit it once already?
MadCatz’s QA sux 
you might have a faulty pcb…
mabe replacing a in-line resistor in the L2 (3xkicks line) might solve your problem.