I also didn't know that and I'm not sure if it makes all that much sense as it kind of beats the purpose of a cooldown. They should really simplify the cooldown periods based on the card levels so you get all your cards back at once instead of new a 11-card Legendary taking 2 days and a 400-card common taking 5 days which makes no sense.
| Legendary | L1 | L2 | L3 | MAX |
|---|
| Cooldown | 15 Days | 10 Days | 6 Days | 3 Days |
| Gold Foil | 10 Days | 7 Days | 4 Days | 2 Days |
| Epic | L1 | L3 | L5 | MAX |
|---|
| Cooldown | 15 Days | 10 Days | 6 Days | 3 Days |
| Gold Foil | 10 Days | 7 Days | 4 Days | 2 Days |
| Rare | L1 | L4 | L6 | MAX |
|---|
| Cooldown | 15 Days | 10 Days | 6 Days | 3 Days |
| Gold Foil | 10 Days | 7 Days | 4 Days | 2 Days |
| Common | L1 | L5 | L8 | MAX |
|---|
| Cooldown | 15 Days | 10 Days | 6 Days | 3 Days |
| Gold Foil | 10 Days | 7 Days | 4 Days | 2 Days |