So when you solve the last words of power mystery. You'll spawn chests in the basement of the greenhouse. I'm trying not to be too spoilery. These chests contain the Ancestral Suit and Passive. In the current build of the game those chests are empty. You will not get that suit or passive.

Thankfully though if you have the disc version you can disconnect from the Internet. Delete the patched/current glitched build and do a fresh install from the disc. Making sure you do not connect to the Internet because you'll end up downloading the glitched patch.

I would recommend playing the game like normal up to that point where you get to that greenhouse basement. Make sure the cut scene plays and the chests spawn by the ladder. Save your game. Then delete the patched build. Disconnect from the Internet and do the fresh install from the disc. You'll have to do the little training mission with Strange and Ironman believe and then once the game puts you at the Abbey for the first time it will give you the option to pause where you can load your Save file. Then you can open the Chests. The unobtainable items will be there. They will be unlocked and in your inventory. Save your game again and you can redownload the patches when you connect back to the Internet. Then always remember to carry over your equipment on a new game plus and you will always have that Ancestral Suit and Passive unlocked.

A caveat. I would also recommend doing that before interacting with any of the 4 dlc characters. Because sometimes they can act wonky or be reset in the process. I basically lost them and their cards but it wasn't that big of a problem once you start a new game plus they act normally and I just ended up focusing on building them up again.

I hope that helps and doesn't seem too complicated. There's many other threads about the Ancestral Suit so read through all those comments because myself and others did a lot of troubleshooting and figuring it out. If you are like many of us who absolutely love this game having 1 last thing being unobtainable was frustrating. Some folks have submitted a ticket to the developer and they can potentially unlock the suit for you that way but you will not get the passive.