civic robin
I had a negative "Certificate" Joker that got copied by an "Invisible Joker". As I had a second negative Joker I was on 7/7 Jokers. When I sold the non-negative copy I was on 6/6 Jokers, permanently losing one slot. I sold the negative Jokers to see if that fixed the issue, but that left me on 4/4 Jokers.
Might be related to this bug: https://discord.com/channels/1116389027176787968/1241091836584656908
However I don't recall the target of the invisible joker being debuffed when copying it. After some more thoughts, I'm pretty sure it wasn't debuffed when I copied it, but it did get debuffed once before selling it. I distinctly remember being surprised that the debuffed certificate gave me the card it generated anyway. The copy definitely wasn't debuffed, when selling it.