I think this is a bug: the first ship in a “Regular” fleet list never fires. This is bad when the AI sends single ships to attack my ‘raider’ fleets in the sea zone around the UK, and then my ‘regular’ fleet attacks them. I get a result of one of his ships fighting a group of mine, and he never fires back. This happened a lot of other times throughout my game, too, where I have whittled down one of his fleets to a handful of ships and only one shows up in the engagement screen, and it gives a great advantage to the guy who has two or more ships in the weekly sea engagement against a single enemy ship, even if it is a single carrier against two or three subs. Note that even in a group of ships, the first ship in the group won’t fire either.