I have the same problem. Purchased via Amazon digital download code and redeemed on Steam per provided instructions. I have the game in uPlay but the DLC doesn't unlock. I have the Hero Edition. This needs to be fixed please. The problem is still happening and affecting customers like me.
Yep just got this game and the dlc doesn't work sent a chat request and got it just to be told that they know about the issue and are trying to fix it which to me is basicly we know about this issue we have no plans to fix it since it's been happening since 2016 go away so i've just requested a refund from the site i got it from and hopefully this will all be over soon.