I'm sorry to hear that Andy. But what you experienced was an avoidable one.
Look at your power levels during your fights. You'd know right away if something was off (a hero missing, naked hero, etc).
That is what I was doing but because of reading the tread I was concentrating on the sub when the problem was with one of the regular heroes. Once I started looking at the fight without concentrating on the sub the problem was obvious.
The opinions expressed on this post are my own as a player, not as a Moderator.