Yes - as we hit the level 12 fortress our fortres was at level 11 (a few minutes before our fortress was downgraded from 12 to 11) - so we had finished also the requirement to get the level 12 fortress - why we need to do it again?
I try to explain how we act yesterday.
1. Our fortress was at level 12 - same as the fortress of our opponents.
2. The other league downgraded our fortress to level 11 to get the requirement to upgrade their fortress to level 13 (worked)
3. Now we downgraded their level 12 fortress to gain also the requirement to upgrade our fortress to level 13 (dont worked)
Only difference: our fortress was at this time on level 11 - So you try to tell me that I first need to level up our fortress again to Level 12 before I downgrade the other fort? Makes no sence for me, because we fulfilled all requirements we killed level 9, 10, 11 and 12 fortress.