Hi, don't know how to define this as a bug, but it is certainly a way the game is not working as planned.
My Sovreign has 20 attack and 20 defense (more or less) he is a fallen emperor.
Alone he has conquered about 15 huge fallen cities full of Sions. Each one of them had about 10 sion teams (9 or 12 sions in each unit). Because he has lots of movement points I can attack the same target several times during a turn. Apparently those units are unable to even wound him, probably because of his high defense skill.
I believe the problem is that Sions have 0 defense and in auto fight they don't use their uberskill. Of course one of those units could just use its special skill and ANYTHING wuld be destroyed. Problem is even in tactical combat they rarely use it even though it would grant them instant victory (sometimes they use it against units that are immune to it).
If instad than autofight I play a regular tactical combat eventually the sions (might) use their uberskill and disintegrate my emperor in just one shot.
suggestion: The Sion skill should be heavily nerfed, they should use it as much as possible, only against units that are not immune. They should also use it in autofight.
In general I also don't like the fact that the same unit can perform the same attack over and over.