This started yesterday, but I noticed it impacts certain flights and destinations.
I tried SIN-VIE and get an error, but SIN-KUL gives me various options:
SQ974 Singapore (SIN) 12:55 Bangkok (BKK) 14:20 0 Economy
TG417 Bangkok (BKK) 16:40 Kuala Lumpur (KUL) 19:50 0 Economy
Multiple Airlines Multiple Singapore (SIN) 15:20 Kuala Lumpur (KUL) 22:35 07:15 Multiple Economy