I’m having this problem too. Huntsman chest piece is duplicated by the munin call tattoo but luckily I managed to reload a save from before I bought it. I’ve seen people report the duplicate galloglaich armour after a bunch of different actions but for me it was after taking some tattoo designs (the floating paper collectibles, not store bought ones) to Tove. Funny thing is this isn’t a duplicate for me, because I don’t actually have the galloglaich armour yet. One just pops into my inventory

I too have been having this problem. Saw some forums from back in October that discussed this same problem and apparently Ubisoft were made aware of the issue and fixed it but clearly that is not the case.