Best way to book Star Awards redemption using Krisflyer miles?

Have I got this right? Can United/ANA/Aeroplan websites be checked for Star Alliance award redemption availability before calling Krisflyer to book?
My understanding was that Star Alliance award seat availability on Krisflyer and the other Star Alliance partner’s online systems would match, but I’m having trouble attempting to book a redemption with Krisflyer that looks to have availability elsewhere.

I’m hoping to use Krisflyer miles to fly return from Ulaanbaatar, Mongolia (ULN) to Taipei (TPE), with a stopover in Beijing (PEK) on the return journey, in December. The first leg will also transit in Beijing.

Krisflyer say there is no availability on the ULN > PEK or PEK > ULN legs on Air China (the only possible redemption airline, PEK - TPE return legs are fine), however online searches on ANA and United both show Star Alliance award availability on those routes, both as individual legs and as a route all the way through (ULN-TPE).
Infact, Krisflyer say there is no availability on those two legs for the whole of December and January, whilst ANA and United both show availability on most days.
(To throw a spanner in the works, Aeroplan shows availability on it’s colour coded calendar but in the list underneath says ‘no results found’ on all days, coloured or not)

Have I got it all wrong, or could there be glitch in the availability?

Any insight is appreciated.
Thanks

Hi,

You can get a fair idea of availabilities via United for example but it really depends whether Krisflyer can see the same availabilities. Sometimes there are phantom seats which are actually non-existence.

Good luck.