During a session, every player decided to focus on giving up one army piece and replaced it with a Fortress. Soon half way during the game we ran out of Fortresses, Had to bring in the second copy and use its fortresses.
Is this correct or has anyone ever encountered this ?
It just happen that each player was playing defensive way.
I usually only build a FORT (not a fortress--that is an optional rule) if I have an extra build at the end of a turn that can't be used to get any extra victory points.
The +1 is significant, but not usually decisive. So I often attack other players who build forts. That may mean that I take one extra casualty--but that might have been the army I would have used to build the fort!
You do realize that once a land with a fort has been conquered, the fort is destroyed, right? Also forts are often destroyed by disaster cards.