If you have multiple favourite heros’ portraits and you want one certain deck have e.g. Sire Denathrius as a default skin for this deck, if you go to play that deck you will still get random hero skin from favourites from this class.
How to reproduct this bug:
Go to your portrait skin collection for certain class. Make more than one favourite. Create or choose created deck. Choose certain hero skin for this deck. Try to play this class. Hero skin in game will be random even though you chose a certain hero skin.
You don’t have to even go to play the game of constructed because if you restart the game, and you go back to your collection this deck that you chose a hero skin for, won’t have it chosen, even though you chose it before restart.