What was the process like disclosing the bug to them? One part of your post that you left out and I was curious on. Was it friendly/straightforward? Were they surprised at all that this was possible?
Pretty nondescript. I just sent them the code and explained how to replicate it. They said they'd patch it and then they did haha. They offered me some in-game currency as a reward (20,000 gems, which I think is equivalent ~115 bucks).
I hope you have the blingiest cards ever now, great write up.