I fight with Battle Timer on, i don't like it when theres 1 bugged enemy infantry unit during a siege on my castle, that i had to fight off tier by tier to the last wall, and 1 enemy unit gets bugged (where its spread out all over the map for some reason, and it isn't getting killed or reforming or retreating) and i am forced to either:
A. Sit for eternity, since the timer doesn't run out.

B. Send what few remaining forces which i likely have very little of remaining out to get slaughtered by enemy cavalry that remained in reserve.

C. Give up a barely won fight against a sizable and actually well coordinated enemy attack, because i can't kill off that 1 bugged half dead infantry unit, which is the only hope the enemy has of getting through my last wall.

To be honest, i don't like those options, so i leave battle timer on just for that reason, so the computer doesn't get bugged victories against me.

(Note: During this battle, my odds were ridiculous either, it wasn't one of those "heroic" victories where the odds are 10:1 against me, the odds were actually quite close, being about 5:6. I had sacrificed a chunk of my defenders to get rid of the enemy trebs and catapults. This incredibly enjoyable fight turned my best moment into a sour bitter memory too. )