Enemy Retreating during Pre-Battle Screen

This has happened twice on two separate occasions now.

Most recently, I (Sicily) attacked a Moorish army besieging my town at Cagliari. The Moorish army had one stack next two it, meaning each side had one reinforcement army. So I clicked to attack the Moors, and the pre-battle screen came up. I clicked to do a night attack, at which point the main Moorish army retreated and my General advanced forward to occupy the tile. My General had also got a trait message, which I couldn't read as it came up when I clicked to attack the army. Anyway, I thought it was bizarre and so clicked to auto-resolve the battle, but I got a CTD and an unspecified error message.

Playing unmodified 1.2 on Vista. Had anyone else noticed this bug?

Well known and already in the buglist. No workaround other than not clicking night attack or using less men to attack.