Just did a solo card farm on BST, only missed the 15k and 30k Magic objectives (derp, should have used Whisker...).
Walked out with x7 Cards, it's fixed.
The NQ Campaign yields a card for every 3 objectives (from my observation), and there appears to be random cards (1-3?) on top of that.
Given the 19 available objectives (3 floor obj., 3 bonuses x2 on floors 1/2, 10 bonuses on floor 3), you are gauranteed 6 if you hit all, and I've observed at least one random card every run. I've yielded 7-8 on most runs.