it's really hard to prove that something is wrong, but I have to admit, that on Schneider I've got plenty of yellow cards and pretty fast exactly what I wanted, even with good exp on them.
With Shae, it took me 6 draws to get a rare card and I'm far away from getting any cards I'd actually want.
So yeah, subjectively, it feels like something is wrong. Still hard to prove anything. We just have to trust the system I guess.
As a suggestion, perhaps pay 5000 to remove a card from circulation, thus in the long run, you can remove every card, except for the one you want.