Not exactly a bug: I was playing the Caverns of Chaos and managed to get to the 8th battle, where among others I had to face 2 security robots as enemies. The problem is that both robots had the same name so when they energised, I couldn't tell which one was going to shoot, so I couldn't get out of the way. This combined with the fact that I was in the middle of a ziggurat layout, with 3 dwarf characters, surrounded by more enemies led to my quick demise. Please make sure that no character has the same name as another in a level. It takes a lot of time and tries to get to those levels and it's very cheap to not be able to make the correct decisions from a thing like this.
Actually it doesn't matter who charged it up because either one can use it, but one of them has to use it.
As @timeracers points out, this particular case has nothing to do with the units' names. That said, giving unique names to every non-minion monster when in minion groups is something I'm considering doing...
