Just called to get 2 business seats on an OZ flight from ICN-SIN. NH shows it as available. UA Rez agent (who was extremely helpful btw) could not even see it. In fact the only way she could see it is if she tried to sell me a revenue seat. I asked her if the flight was just zeroed out for award availability and she said no - it literally doesn't even appear when searching for award tickets.
I'm afraid StarNet filtering is still alive and well folks