This is the section of the manual that covers mix mode being able to inflict damage both on a carrier and its aircraft during an interception.
Okay, this is close to what happened, so I gather it's not an unintentional bug.
And I realize that sometimes aircraft followed other formations to their carrier, as at Midway. And I realize that my "mixed" escorts include bombers.
But it still feels completely wrong. I ordered a bombing mission against one ship, and another one (which was quite far away) explodes and sinks. This sequence of events will happen every single time under certain circumstances simply due to the fact that the anti-ship attack value of the escorts is applied to damage the escorting carrier. In real life, the escorts would tend to stay close to the main bombing mission and wouldn't venture out across the sea every single time to chase the enemy escorts back to their other carrier. I mean it's plausible that this could have happened SOME of the time, but certainly not every single time. Escorts are supposed to protect bombers, not leave them to venture off hundreds of miles to attack an enemy carrier that launched an intercept CAP.
AFAIK carrier intercepts are treated exactly like land fighter intercepts but that doesn't seem realistic to me. I mean they weren't really able to intercept enemy strategic bomber formations attacking targets hundreds of miles away; getting all the fighters up from down below via the elevators and launching them was a much more time consuming process than scrambling interceptors from a land base. Not to mention few carrier fighters were good at fighting at 25000 feet.
So perhaps it might make more sense to limit CV intercept range to 1 (and not increased by upgrades). A carrier could provide CAP but only for adjacent hexes (usually friendly vessels). This would make long range intercept self-destructs impossible. It would encourage a mutual protection formation of carriers and escorting vessels, sailing close to one another instead of spreading out alone over the ocean. This might be more 'realistic'. And it would also perhaps more accurately represent the limitations of carrier air defense, where even with radar warning, getting fighters into the air before the enemy arrived was barely possible, much less intercepting enemy bombers striking another target a thousand miles away.