It happened to me tonight while leading a formation of b-17s. A con 109 hit my lead plane, knocking out 3 engines, ball and tail gun before I killed him. The lead plane was smoking the way you would expect with that kind of damage. Neither of the other 2 planes were smoking but each had the exact same damage as the lead plane. A few minutes later when the 4th engine died on the lead b17, the 4th engines died on the other 2 planes also.
While we're on the subject, the 50 cals on the b-17s didn't seem to do nearly as much damage as they would have under v1.09. I lit up that con like a christmas tree but it survived long enough to put 1 short burst into me. That burst did a lot more damage than I would have expected also. (3 engines, cripled the 4th and 2 gun positions) I'm wondering if buff guns and armor have been tuned down in 1.10. It certainly seems so.