Sorry to interrupt you guys, but eligibility has nothing to do with the nationality of the applicant. Nationality only might affect the criminality and security. But, as @kattarrina said, nothing has done on her file except R10.Maybe.. just maybe your case is scrutinized a bit more because of recent history of Serbia? Or because they are checking criminality through your country's agencies. Whatever it could be, I am guessing it's related to your country of origin. It's all just a speculation.
One thing though is that Calgary and Vancouver are much smaller as compared to Ottawa and Sydney, and they do redistribution very often.
It seems that it is just your luck. No analyst opened your file to check your docs. They only checked the completeness R.10 and they verified that you uploaded everything!