I'm a fledgeling DM and I used an AL Dark Gifts resurrection on a character in a home game of Curse of Strahd. He randomly got his eyes removed for 60ft blindsight, and at the time I kinda assumed that, since he didn't become a bat, his blindsight is magical and a 60ft sphere that sees through walls, which I happily announced.
Now he spoils the whole campaign since that kind of sight turned out to be a superpower on par with Spider Sense, even if I say that he doesn't see all of his 60 feet bubble at once.
The question is, how do I remove the curse from him logically, beautifully and inoffensively? The guy doesn't abuse it and loves his empty eyesockets, so I don't want to pull a "godly intervention" out of my… hat.
Best Answer
If you are looking for an "in-game" resolution Ravenloft, and by extension Barovia, has always had a history of twisting things to its liking. The Demiplane of Dread is quasi-aware after all (or at least was in past editions). There is ample room for the environment to adapt to this advantage and thwart it, the walls can become more and more opaque over time to this ability as it adapts.
Another idea is that it could also change to start picking up "false positives". The ability could indicate the presence of things that are not actually there or at least not perceptible to the others but harmless. Like the spirit of a dead girl could set it off as she watches from the sidelines of a battle. He could freak out at "seeing" something more on the battlefield that can cause confusion and mishaps during combat.
I think that Zeiss Ikon has it right that you can just renege on the gift but I agree that an in game solution is usually best for flavor. Then your issue will be when/if they leave Barovia you will have to figure on a "fix" at that time. Or you can just say that the alterations by the Demiplane were fundamental and can't be reversed. Maybe the sensory overload was amplified by the Demiplane so that his brain can no longer process the input through solid objects?
These are not RAW solutions and simply based on flavor and experience over years of dealing with Ravenloft in books and modules. I personally would have limited that to 30ft, but that is my table not yours.