I am looking at option to book some award on sk metal. The availability seems to be there, the award calendar shows low level 15000 points

The award is goh cph osl xxx where xxx is any airport in norway

When I simply search goh cph osl, it shows the flights and points after seeing 15000 low level in calendar view. When i do the same for goh xxx search where xxx is another airport in norway, it wont shows any option despite there are multiple dates with 15000 points

Osl xxx individually does show 5k options (that would connect to 15000 option for gph cph osl.)

Is it some type of bug or restriction on sas app?