Bad credit behavior

I got denied a World Elite MasterCard this week at National Bank and the account manager said it was due to "bad credit behaviour".

My credit score is 713 TransUnion, I have no missed payments, no derogatory marks, statements always paid in full, 42% utilisation.

The only thing I can think of is that's because my credit file is 10 months old and has 7 hard checks (most of those were before I knew what a hard check was). Is this enough to configure "bad behaviour"?