As expected an argument of the same sort that your facing broke out.
No, it is a bit different situation. It is the agreement collision and in the situation we're talking about there's only one agreement and thus no collision.
Btw, I find mutual defense agreements a bit strange and worthless but that is only my opinion.
I like the idea of posting on the individual game site the agreement when made and when over...there is never a argument unless you can't count to 3 before attacking....