So after doing some digging. I think the reason you can dupe cards is because when you have 2 of the same packs the games code thinks you are placing down the modded pack and not the normal. For example the game reads the packs as Princess Princess_Lucky when you place down Princess the script is really trying to place down Princess_lucky. So it checks if you have any princess and it does. so you can just place down inf. Its super hard to explain and grasp the idea but I can try to explain more.

Waifu Script
![[KEYLESS] SkidZero Script](/_next/image?url=%2Fassets%2Fscripts%2F69fd92a6cd95ac4f70ad023e_1778225830951_I2rXuXOoWB_0.webp&w=128&q=75)