Qantas flight award discrepancy

I’m searching for Singapore to Dubai for 30 August and there are no business class seats available at all.

However, if I search Kuala Lumpur - Dubai (via Singapore), there are business class seats, including that Singapore leg that I searched for above.

So the system is showing available seats if I start my journey in KL but not Singapore. Is this a common problem with Qantas and how do I get around this?

I wouldn't even bother to be honest, but don't get your hopes up of securing it. I had same issues with Qatar Business reward availability. QF customer service advise if it's not on the website it's not in their system..

This doesn’t look like a discrepancy but an example of a married segment where airlines make inventory available based on origin and destination rather than the individual flights. The only possible way around it is to call and beg the airline to separate the segments. But you’ll be facing an uphill battle given you’re wanting to use Qantas points for non-Qantas flights, so expect Qantas to have limited or no ability to unmarry the segments.

I’ve seen that many times when trying to redeem QF points on partner airlines, e.g. Air France, KLM and Qatar Airways. I ended up not flying at the time.

I've seen the same recently when trying to find business award space Melbourne to Perth. The direct flights had no availability. If I tried booking from Sydney though, it offered business award space from Sydney, connecting in Melbourne, then onto Perth in business, on the same flight that said no availability if going directly from Melbourne.