I spoke with QF yesterday to insure that the bookings were linked and asked again why they sell on their website a connecting flight through SIN with less than 1 hour connection time.
She had confirmed that IATA specifies a minimum connection time of 1 hour in SIN. She asked where on the QF website I had seen the routing and after confirming it she said that she will put the request to IT that it defies IATA regulations and to remove it as connecting option through SIN.
Interesting to see whether QF follows up on this error.