Interestingly, Tony Druce, didn't recognise Celmisia discolor as any different from C. incana and, accordingly, he subsumed discolor into incana. For that reason C. discolor wasn't ever included in any of Tony's masterlist iterations and it seems that Shannel Courtney has adopted a similar position in his ongoing updating of Tony's original masterlist. In Tony's local and regional lists, he denotes discolor within incana. I'm not suggesting that that explains the factsheet absence, though.
Cheers, Geoff R