Sailors get knocked over board even with 0% risk

Hi,

I've now multiple times run into situation, that when my ship has returned to Kingsmarch, one of it's sailors has gotten "knocked over board", even thou shipment has had 0% risk when it's left.

Is this some mechanic that despite of 0% risk, there's always a chance that crew member might get removed from the ship?

Seems so.

Risk modifies the chance for something happening to the shipment. It appears to have no impact on crew members leaving and the pirate boss capturing your ships