[LAU] Alesis Control Pad and Hydrogen

Hello, An Alesis Control PAd is connected to Hydrogen. Channel 10.b It works although quite often when hitting a same pad, the Hydrogen instrument would not sound but instead some kind of a click is heard. Makes this with any Hydrogen instrument. When I connect an Axion 25 to Hydrogen and use the rubber pads, the Hydrogen sounds are always heard, no matter how fast a hit is repeated. Has anyone seen that kind of behaviour before and is there something to do ? I tried varying the Control Pad sensivity/velocity curve/threshold but still, the Hydrogen instument is oftentimes replaced by a click. Thanks !