New Moto Guzzi Door Mats Available Now
I haven't seen too many of these that were adjustable, on any bike. I'd check for wear (and therefore play) in the lever and especially in the main pin that is the axle for the lever - half the time that's why I end up replacing my levers...
The parts designed as sacrificial (intended to wear first) are #3 and the actual clutch lever pivot hole that it connects through. Once these are worn, the play allows the lever to move enough that it will fail to reliably depress the pin on the microswitch.