@surfer Very good information, thank you.
As long as we cannot reproduce the issue, we have no chance to dig deeper in. But as it “healed itself” there is nothing to worry about for now.
I saw someone mention earlier about sub hits coming off first.
I believe a DD changes when a Sub fires. With one, a sub fires when everything else does.
So I think a defending sub would fire in surprise strike, but the attacker sub would fire with other units if the defenders have a DD.
Also in the opening fire phase, sub hits could be taken on defending subs that also fire, thus preventing a unit from not getting to fire if you have enough subs to cover the hits.