I'm no expert, but I think they are fatigued and only hit on sixes? That is assuming they took the option to strike back during the initial attack.
FATIGUE
After attacking in melee for the first time during a round, either by charging or by striking back, units only hit on unmodified rolls of 6 in melee until the end of that round.
I think I know where my issue came from, in the full/advanced rules the move back rule is under consolidation moves on the next page...