hundredth black market card not working

[asi14]

So according to the description of the hundredth black market, any card that i hadn't gotten from a stage yet as a result of clearing it will then appear in the black market. So far every time I've tried using this card, I've only gotten the regular 50 money bonus card, not any actual cards. Is there something I'm misunderstanding about this card?

[An Ordinary Noob]

Check you haven't unlocked all cards from that stage, if so, play on harder levels.

Plus, to unlock the cards you have to specifically pick them after defeating the boss, or being dropped (and picked) with the doremi sweet card.

Tldr: cards won't appear magically after finishing the stage, have to be picked in the end.