My ship's crew simply started disappearing, despite good morale (70+), plenty of food and drinks, and no events/encounters that might have resulted in deaths.
I must have lost about 10 crew members (active duty+reserves) in the last couple of hours of gameplay, and there are no new crew members to be recruited in any port/tavern.
Any clue, anyone?
Addendum - I noticed that the crew never falls below three members. Even if I hire new ones, they'll disappear within minutes, but 3 will remain.
Savegame - https://drive.google.com/open?id=1CmucjOaWTDB8bZ2I_0elF8C-WjISINRY
output_log.txt