Some units lose rally points?

[Spledge]

Why do some units lose their rally points during a battle? i.e. in mid-battle, when in contact with their leader and NOT under distress, their rally points drop to zero and thus can not rally.

Thanks.

[Mobhack]

Your unit has failed a rally (of itself or a subordinate) this turn, so cannot perform any more rallies, hence chance=0.

The rally value will be restored to book value next turn.