Logged on and received an attack notification. Then the hero has lost stamina window. 19 hp remaining. Then 18, 17, 16, 15, hp bar keeps dropping, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 hp remaining. Wondered if I got blitzed by a string of attackers. Looked at fort and the hero was just standing in the cell at 19 hp which I left him at. He was training during the attack and I guess the indicator took his health to be 0 hp and started changing to match it.
If they are training then they can't be active in defence - looks like the program hit a scenario it didn't know how to cope with properly.