KAD32 problem - Cant stop the engine

Hello all,
I have a vessel with twin Volvo Penta KAD32 engines. Model year 2003.

Often in this year - the engine on the BB side will not stop when I rotate the ignition key to stop the engine.
If I look to the black box on the engine, I see the automatic switch is broken.
When I the automatic switch push back and rotate then the ignition key - the engine stop correct.
There are also 2 switches, to stop the supercharger if I drive slow on the Netherlands canals.
This could also be a problem ?

What could be the error ?

Thanks for your help.

Hi guys, no ideas ?

Could it be that the relay or the speed relay is defect into the blackbox on the engine?