Someone found a bug in 0.8.1 whereby enemy ships could kill nonexistent crew, thereby causing a system to have a negative number of crew inside. This, in turn, would cause the system to be “negative repaired” by five times the number of anti-crew per turn. This would cause systems to have negative hitpoints, making them exponentially more susceptible to crew damage. If crew were not manually reassigned, the negative HPs of the affected system would cause the ship’s overall HP to drop below the critical 40%, causing it to be destroyed.
I have fixed the bug, and the update to address it is uploading as I write this. It should be available for download
within a couple hours eventually (see below). The launcher will detect it automatically when it’s ready, but if you downloaded the full archive, you’ll have to manually reinstall.
EDIT: For reasons unknown to me, the server is rejecting the update every time I try to unload it. I will try again in a few hours and, if that fails, sometime tomorrow. Until then, unfortunately, you will have to put up with the bug.
EDIT #2: As of 25 November, the server is still rejecting the update. In the meantime, I have found that breaking contact with an enemy (moving >1 tile away so they can’t attack) and manually setting the crew in a negative-crew system back to zero will stop it from decaying. Then, repairing it by actual positive crew repairs, scrap, or at the shipyard can bring its HP back into the positive numbers.