引用自 Wok：

Hello! I have a question, the first games I idleed I could refund, but now the games always go by 3-4 hours and I can't refund, help!

When you refund a game, any game, for the first time, Steam disables card drops for the first 3 hours for all subsequent games purchased (This cannot be changed back to my knowledge but feel free to try open a support ticket to Valve asking to have the flag removed from your account. Best of luck with how notorious Valve's support can be).

Why? Because people kept buying games, idling all the game's cards, then refunding them and keeping/selling the cards. That's a loss for Valve, so they stopped people from doing it.