Suicid Wall Jumper

[Tartaros]

a little bit strange,i besiege syracuse as romani. on the wall, only toxotai and low pelts fight against my samnite heavy infantry.
normally i only loss 5 or max 10 of my units jump down the wall when figthing. finally the samnites loss nearly half, 38 man, but only 4 where killed in action - the rest are suicide jumpers... is this a bug or the combatbonus for the defenders?

did someone has the same experience or a antitactic for this jumpers?

greets