I was exploring the map and started a fight on this sector. I had 4 full packs of 12 sword dancers and one of 7 and as soon as I assigned them all and hit the "start" button, the error showed up. It said "internal error" with a standard error-text which I believe started with "The system caused..." and then te game reloaded in my town. When I went to fight again, I noticed that a pack of 12 sword dancers were lost, so I only had 3 packs of 12 and the pack of 7 left.