Any ideas why Thai Airways award availability from Bangkok to Brisbane is no longer available?

I am checking out availability (via Lifemiles) on Bangkok to Brisbane flights, which appears to be nil while there is some availability Bangkok to Melbourne and Sydney.
We have managed BKK-BNE flights award flights on Thai via Lifemiles twice last year and have one booked for April this year - don’t know why BKK-BNE is now “not available”?

Does anyone know why this is happening ?

I note that the Lifemiles will be upgrading their website from 1-5 February.
Will this make a difference??