When the ground screw came loose the voltage coming out of the flap switch traveled back up the feathering ground, causing the system to think the feathering switch was activated.
When part of an electrical circuit starts to "float" like this - becoming no longer anchored to some global reference voltage (usually chassis ground is considered 0V) - the observed voltages in other parts of the system can take on really byzantine values.
When part of an electrical circuit starts to "float" like this - becoming no longer anchored to some global reference voltage (usually chassis ground is considered 0V) - the observed voltages in other parts of the system can take on really byzantine values.