No but I delegated my cards to wattle.
I will try to upgrade cards.
Unfornately there is a cool-down phase after I upgrade cards, because I must cancel the delegation, upgrade card by me and delegate new.
So in every case I will see that this spoils not your ability to play and I will take especially attention for the end of the season, so that you can play with all cards with cool-down in the last day of the season.

Wish you good success !!