If you are talking about touching any where on the metal case, I am wondering if it also happens when you touch the plastic. IIRC, the ends on either side of the keyboard/PB/Mod Wheels is plastic.
On the one hand, if there is a grounding issue, I hope you are wearing insulated shoes when you touch the CZ. On the other hand, back in the late 80s, I damaged a CZ-5000's electronics by zapping the CZ with a "small" discharge of electricity.
Damned if you do, damned if you don't. I recommend getting it looked at by an expert before risking further damage. JMO.
Steve