I gather most of the issues are not changes as such (although there are some, like removing the CCTV screens from the drivers cab to ensure the DOO beast doesn't rear it's head). The biggie appears to be TfNSW signed a contract for the train platform without having also locked down the internal fit-out and put that down as 'we will sort that out later'. This was to lock in the build in CAFs order queue. Then when the first iteration of the desired interior was presented, they didn't like the price CAF were offering.
TfNSW got outsmarted by CAF, TfNSW is in a position where the builder calls the shots.