A faction has peace treaties :
"peace": {
"13129": 1495531145,
"24884": 1475144866
}
A faction does not have peace treaties:
"peace": [ ]
The first is an object (dictionary in this case), the second is an array.
http://www.json.org/
This kinda screws with my json to object mapping ... I can do a work around, but this looks like abug to me.