Oakenheart shield switched from epic to uncommon in the latest patch (?) - rewarded as epic from premium Defense of Woodhome.' Edit: Correction, it's the reward for the second premium dungeon, Forest of Souls! Also, see that some of the other rewards have switched in rarity, so this might be work a change in card weight as mentioned below re: unskilled slots).
Also noted that unfilled racial slot for humans and elves count as uncommon, but common for dwarves. Maybe a result of changing card values somewhere? Edit: noticed uncommon/common variations of a lot of unfilled slots. Intended or not is hard to say.
Not every reward has to be epic but uncommon seams a bit low since that shouldn't be too hard to come by on your own. They will probably replace the item with something else nice catch either way.
