When I look through my gallery, filter by "Treasure" and go through each deck (B, 1, 2, 3, ...) and go through all card types (Weapons, Spells, Armor, ...) these are the only ones that appear that are blank.
I'm assuming you're referring to the much longer list of cards that used to appear that the devs said they would fix. If you're talking about that, I agree with you, I had no idea they fixed it and any information about the fix is very hard to find.
I took a shot on a whim to open more chests and unlocked a few I was missing, but I am still missing these 15.
At least I know now because of you that the Squire and the Flaming Returning Throwing Axe +1 are able to be had through chests, and the Samisen and Black Arrow Longbow are campaign rewards, not chest rewards.
If the community can chime in about the other cards, I'd appreciate knowing before opening up other chests.
Also if anyone has a link to the official news of fixing all those originally bugged chest cards, I'd love to read the official statement/patch/release notes.