I've seen a few messages on expat forums this year about this subject. People being granted visas only to be told at a later stage that in fact they have been declined because of computer error.
I saw on another forum that one particular SFV candidate who had been refused later down the process because of this issue was drumming up interest to make a mass formal complaint.
Immigration NZ have had issues with the SFV and the online portal every year I've been interested in coming to NZ (since 2008) - servers crashing, portal becoming unavailable mid application, not being able to submit payment info etc etc.