When I handed in my first 4 order medallions (or maybe reporting on London being free of the order) my Galloglach Armour (that I was wearing at the time) was duplicated. Both versions were superior quality lowering my original set from mythical quality. Reloading a save did not fix this and I have been stuck with the second armour since.
Muninn Call Scheme (Front) can be bought, is added to your inventory, but then you visit your tattoo artist it is not available for use. Once leaving the shop the scheme was removed from my inventory and my Huntsman Armour was duplicated and both versions were superior quality lowering my original from mythical quality. Reloading a save was the only way to "fix" it but it happened on each subsequent attempt.
Also one of the hair styles is misnamed either by the Trader or tattoo artist. It's called Savage Hair (all colours) by the tattoo artist but has another name in the Traders store. No real issue here, just something that (I think) should be a small patch.
Cross Face, Vidarr, Warrior Tears can all be bought from the Trader despite being from Treasure Horde Maps. When the maps are completed after buying the tattoo you get nothing.
All the Dupuytren Emblem tattoo schemes are called "Auki Sign" in the Trader's shop.
The Vegvisir Scheme (Front) found in Lunden is not added to the tattoo shop but the paper is removed from your inventory.
All parts of the Asgardian ship can be bought from a Trader and by completing requests for Arth. You get them twice in your ship menu.
The Seer Sail is not able to be found. I'm guessing that it's from the Treasure Horde Map at the house with the pool where the Deringer is.
One of the maps, I can't remember what one, stays in your inventory even after finding the treasure. I think it's one in a well under a tree.
Not sure about this one. I didn't loot the head from the moose in Vinland. I did expect this to be a secret alpha animal.