Not sure how this can happen! What’s going on SG??? Russians just get to keep hitting?
This is a known bug and is thought to be only cosmetic. I’ve seen it triggered when someone reserves a battle on an opponent and then does not actually start the battle. Sometimes the system forgets to add that flag back to the attacker so he goes into the negative.
There was a thread on this exact bug, but I think it got moved under the general ‘war bugs’ thread.