Every time a battle starts, the enemies die instantly and I win without doing anything. Why?
The most likely cause of this symptom is that you forgot to give your enemies any HP. If they have no health points, they will die instantly, and you will win instantly.
If you are sure that you have given all your enemies HP, make sure that you have not made a formation entirely out of Untargetable enemies. (check the bitsets in the enemy editor if you aren't sure if your enemies are targetable or not) Alternatively, you may have set all your enemies to Die without Boss and forgot to add an enemy with the Boss bitset.