SIN-DUS in J cleared a few days ago for June 30 (for one person). It cleared 6 days after I had waitlisted the flight.
I have already made other arrangements that work even better for me so won't ticket it.
Ticketing deadline is today. If you are interested in this sector, watch out if seat will become available again.
I was actually very surprised that I couldn't redeem SIN-DUS outright as I had heard that utilization is very low. Not sure I fully understand this game that SQ is playing: what really changed in six days that made them suddenly release that seat?