+1 the new skin is only applied while in dungeons, which is very sad.
When selecting Grimms as map avatar his icon is updated but the unit art remains the same.
Tried selecting a different hero and then selecting grimms again, no dice.
Tried restarting the game, no dice.
Confirmed with house members my map avatar still looks like the default skin.
Ran a dungeon, can see new skin only there.